Sevtech: an obsessive guide

You woke up one morning on the beach. Started walking, it's your regular routine. You were on the search for... Something. What was it? Something pale blue, shining... the concept escapes your mind. What were you doing again? It's hard to remember anything... but you do remember a pattern of 9 squares inside a larger one. Maybe if you saw it again, it would help you remember.

Welcome to existence! How does the sun feel? The grass? If you're allergic to fancy green things (low or choppy fps after the initial chunk generation has calmed down) consider opening up your mod options and find "better foliage". Open up it's config and turn the "enable mod" setting to false.

Now existence is great and all, but you really are stuck to the dirt monke lifestyle in this early half-age. Until you make a crafting stump, your only real tool and weapon is the flint hatchet and your only real options for feeding yourself are wild berries and raw carrots. We wouldn't want to set a bad example for the talking heads, so lets get past the nuts and berries stage.

Punch grass for plant fiber
Punch leaves for sticks
Punch gravel for gravel
Punch rocks for flint flakes
Punch tree (with tool) for wood
Brain blast

Haha, Punch Many Things. But, there is some nuance here.

Don't focus too much on gathering plant fiber. The stuff is everywhere, you'll have more than you need after a few seconds of spinning around in tall grass with m1 held down. (And theres a trick to easily get as much of it as you want later.)

If you spawn in a forest, gathering sticks off the ground piles is way faster than attacking trees for them. Scoop up as many as you like.

The only reason we need gravel right now is to get flint. If you can't find gravel, don't worry. If you dig up enough dirt and grass blocks, you will eventually come across some flint. This is time-inefficient, but it's better than nothing. I recommend looking for water, as gravel is often found on the shore. However, if you come across a huge deposit of gravel, consider slapping together a few fiber torches and using the drop-on-torch trick to collect it all faster. The unlit ones work fine, and you can later toss them for inventory space 100% guilt-free if you need to. If you do find a gravel windfall, go ahead and use up your fiber mesh entirely. That 65 gravel will last you well into the next stage.

"Why can't I move items to my offhand?" you might be asking. It's because of a keybind conflict. Specifically, the one that controls fluid mode for one of the later tech mods. I've never had to use this keybind even during its relevnt age, so go ahead and rebind this to whatever you want.

You can usually find everything you need to finish out this stage by climbing the closest tree and looking around. Don't think too hard. Wander a bit if you need to. Be monke.

There's really no reason at all to delay getting your crafting stump. Cut down a tree with your new tool, and lets move on to something more interesting.

This feels right. Placing things on a grid, and bashing them into the right shape. You feel like it is more difficult than it normally is, but can't remember what it's supposed to be like. Straining to conjure up the reason why, all you can come up with is the mental image of a hot, grey box with holes in the front. You haven't seen anything like this around, but maybe you could find it somewhere?

Nice brain you've got there. Ready to use it? Hopefully you haven't moved too far from your flint knapping spot, because you'll need some more flakes.

Expect to be in this age for a while, especially if its your first time. There are a number of items you need to gather to advance, and you don't have many methods of bending luck in your favor. You'll be doing a lot of walking- so keep your eyes open and be ready to make a detour if you see something valuable.

Nature's compass
8 Sugar cane
4 Bones
7 Clay
1 Ink sac
1 Shark tooth
1 Shadow gem
Leather
4 Buffalo teeth
a handful of Red cedar

bone shears
a handful of Dark Oak Wood
some kind of vanilla sapling, preferaby birch
an abundance of clay
an abundance of wool
brown mushrooms
animal skins
at least a dozen berry bushes
bone blocks
mulberry saplings
at least 32 shoggoth flesh
at least 14 monolith stone
at least 1 iris (tall purple flower with tall leaves on either side)
vines

Before we get started, allow me to introduce you to . will be your loyal and unwavering companion in not just your age 0.5 journey, but potentially your entire Sevtech adventure. will never leave you of 's own free will, will never break, and while 's damage output is modest, will never, ever fail you. Unless you throw by accident. As long as you don't do that, will faithfully follow you to the ends of earth and beyond. We love . Upon entering age 0.5, your first action should be to craft and place immediately on your hotbar. Yes, I'm being a bit silly. But genuinely, treat your well, and will be there when everything else fails.

The second thing you should do is work on crafting Nature's Compass. The materials are usually fairly easy to get, especially since most anything you kill has a chance of dropping bones. Take your newly crafted and go on a wild rampage, killing anything that you see. As soon as you get a bone, knap it down and get crafting. use the nature's compass and start searching for the darklands biomes, to see which one is closest.

Chances are, the darklands mountains search will turn up nothing. That's pretty normal. Ignore the sludge plains option as well, that biome is in an entirely different dimension and you'll probably never use it. Honestly, I'm not sure why it's even there.

Typically you will notice one of the darklands biomes within 1400 blocks. (Usually the forest.) You could make a beeline straight for it, but not all of them are created equal. If you see either the plains or highlands are equal distance or even a little further, I recommend going toward them instead, depending on your circumstances. In the highlands, it is easier to see and fight shadow enemies, which will drop the gems you need to progress. In the plains, it will be easier to find and herd livestock toward your base, and you will need cows to progress. The choice is yours, in the end. If you aren't a fan of the place the compass leads you, don't worry. You won't be stuck there forever, and age 1 brings a very powerful tool for relocating your base.

If you have the flint for it, making a pickaxe and workblade before we start moving might be a good idea too.

Time to move. Use your compass to decide on your destination and get walking. Keep your eyes peeled, your journey could prove to be particularly dangerous. Keep an eye out for steppe wolves. They will swarm at you on sight, and if you spot a few, there are usually more in the area ready to ambush you if you make them angry. Likewise, be careful when jumping in the water. Sharks and pirhanas will kill you very quickly, and they move very fast. A raft is absolutely necessary for crossing large bodies of water, letting you pick off swarming pirhanas with relative safety. Sharks will still break your raft with a single hit, but with a steady hand, you stand a good enough change at fighting them off. However... every danger is it's own opprtunity, and there are many valueables you can pick up along the way.

In a rough order of importance (aka, what you should prioritise keeping in your inventory), here's what you should look for.

Squid. You should kill squid on-sight. You should go out of your way to do so. Their ink sacs are THE key to opening tech progression, and if you haven't got one by the time you get to the darklands, you might be unable to progress much until a costly and slow RNG roller deems you worthy. Also, if you come across a village, having an abundance of ink and feathers might net you an early atlas, which is nice, but definitely not necessary.

Sharks. You should also kill sharks on-sight, but you can stop after you get a few teeth. Their meat and skins are nice, but not very valuable compared to other things on this list. Just always be aware of their existence when crossing water, and remember that 1-block water isn't deep enough for them to swim in. Pro tip: to most reliably hit the shark's wonky hitbox, aim for their front lower fins.

Natural Cobblestone/Mossy Cobblestone. This stuff appears naturally for only a few reasons. First, water and lava mixing. Second, dungeons. It is worth peeking into dungeons for their loot, which can include shadow gems. If you use seed k, you've already got more of these gems than you need and the danger is entirely optional... But probably still worth it. Scoop up some of the mossy cobblestone you find as well, it will be a surprise tool for later. Just be careful around spawners, any shadow enemy can kill you in less than a second at this point.

Dark Oak Wood. You won't need this right now, but if you pass by a dark forest or see a hut made of the stuff in the wild, you should absolutely take some wood or saplings with you. It can save you a massive headache and an unreasonable number of hours later.

Clay. You need at least 7 clay to get started, but you will need a lot of clay over the course of your Sevtech adventure. 2 stacks is a pretty good start, more is excellent. That said, it is plentiful enough that only the first stack is worth fretting over.

Bones and sugar cane. You need at least 8 Sugar cane and 4 bones to do all the necessary totemic rituals. Grab sugarcane when its convenient, and kill every pig you pass by. They will likely give you all the bones you need, and set you up with ample food and skins to get you through the next ages. Cows are also a good target, and you may as well kill any sheep you come across, until you have a set of bone or flint shears. Just be aware of how close you are to your destination. If there aren't any cows near it, then you'll regret having killed the last ones you've seen.

Some kind of vanilla tree. By vanilla, I of course mean "not from a mod". They are the only trees you can use in the process of curing hides. If this sapling is a birch sapling, then it will enable us to make a base anywhere we want to in the next age.

On that note, let me stop you for a moment to discuss cows. There are two general approaches you can take when it comes to this journey. You can do it all in one shot, or in a few parts. IF you have all the items in the list up to this point (excluding the dark oak), you may want to set up camp near the next group of cows you find, craft some cabinets (they are better than primitive chests), and settle in to breed buffalo and make leather. With leather comes the earliest backpack, meaning extra inventory space to carry more valuables with you when you continue. The buffalo teeth will also mean that you can get right business when you arrive in the darklands. I don't usually do this, preferring to do the journey all in one go, but it is a perfectly respectable option. Go ahead and read the next section "The Hideout" if you take this early stop, you'll find useful info there.

Bone Blocks. In this age, farmland can only be made by crafting a dirt and a bonemeal together, and your options for making bonemeal are all tedious and not very rewarding until you're nearly done. The best way to make farms of any considerable size is to grind bone blocks. You don't need that many, but if you haven't found any at all, you'll be stuck scrounging for extra bones and using the zaphkiel waltz repeatedly to squeeze food out of your 5 blocks of farmland.

Wool. It's the easiest way to get string, and having a stockpile is really nice.

Berries and Brown Mushrooms. Berries are probably the most reliable and least effort food available in the game, and having many of them growing will make your life much easier. The mushrooms will combo with the berries to make a POTENT meal combo that we will get to in the next age.

Iris. Remember when I mentioned a trick to easily get as much plant fiber as you want? Here it is. The iris has an interesting property, probably shared by some other plants, but I actually haven't checked them all. If you break an iris by hitting the top block, nothing much special happens. But if you break the bottom block, it will drop plant fiber with the same likelyhood as tall grass, as well as dropping itself. with a small stack of around 6-10 iris and the right arrangement of blocks on the floor, you can hold right click and spam left click as fast as you can to harvest large amounts of plant fiber by repeatedly breaking the same iris o9n the same block dosens of times. this requires no input like bonemeal, only needs a few blocks of space, and works very quickly. It's easy to underestimate just how useful it is to be able to manifest as much plant fiber as you need at any given time. By all means, experiment with other flowers and see if they do the same thing. I know that not all of them do, and was content to settle on the Iris as by flower of choice, since I think they are pretty, easy to spot while travelling, and common enough to collect between the described destinations in this guide.

Mulberry, Monolith stone, Shoggoth flesh, and vines. These are nice to have, but are by no means necessary. Only grab them if you have comfortable inventory space, are confident you won't be ambushed by random wolves and sharks, and are comfortable sticking in one spot long enough to collect them. They'll be useful later, and usually aren't that hard to find once you need them... But I've lost that bet a few times before.

An honorable mention: animal fat. By no means should you pass up anything else on this list for animal fat, but there's a good chance you'll end up with some in your pocket. Animal fat is the gambligant's preferred food; slightly dangerous to collect, and usually a pretty bad food item. If you're lucky though, RNG might bless you with a FULL hunger and saturation refill, with the saturation potion effect for a short time on top of it. Don't think too hard about how it must feel or taste.

You made it! welcome to your new home. I hope you're comfortable with the dark blue grass, grey sky, and wierd noises the neighbors make. Kick back, cut down a tree, and get to work.

If you've had good luck during your journey, then the only thing you actually need from this place is the wood from the dark trees and the abyssal zombie flesh. And you might not even need that flesh, if you got very lucky and knew what the future holds in store. If you're eager to get out of here, set up a slapdash campsite and focus on progressing through the age by collecting whatever key items you're missing. You'll have your escape soon enough. The strainer might be of use here if you need sugar cane, ink sacs, or teeth. Once you've set down roots, it's frustratingly unlikely that the waters near your home will have any useful critters in them.

Once you've got your bison tooth gear, go right on ahead and finish out the age by grinding out some porcelain. Take the oppurtunity to eat a variety of foods, those nutrition buffs will be super useful through your entire playthrough, and this is where you can really begin to commit to filling each food group. If you've made a horse mill, then flatbread will do just fine to fill out grains as a grinding snack. You only need 12 porcelain to move to the next age, but I recommend making 40. You'll need 32 porcelain for a fully functional melter-basin-table setup with two spigots, and the last 8 go toward a tank to use for melting iron. Technically you can get away with less, or substituting some with seared brick, but the process is very similar, and it isn't worth the hassle. Just make the 40 porcelain, and don't fire it all into bricks right away.

On the topic of shadow beasts...

Shadow beasts are guaranteed to drop at least one shadow gem when killed, and are, by a huge margin, your most valuable target. They are very capable of killing you in return, but aren't as scary as you might think. Their blinding smoke attack actually does very little damage to you, and if you get one by itself, you can easily keep it just at the edge of your vision while blinded and stab it to deaeth with your . Fighting it like this is pretty spooky, as you will be erased from existence with only a couple hits from the beast, but as long as you play extra safe, engage at full health, and triple check your surroundings to make sure nothing will ambush you, this is a fight you can win every single time. Keep in the back of your mind that not every attack you land will knock the enemy backward, land crits whenever possible, and don't let your greed win out over your caution.

...

OR, you can made a 4 block tall pillar and be safe from most threats. Ghouls and zombies cannot reach you this high, and skeletons cannot melee you. Trumpet skeletons might be able to knock you off, but they are likely to pull aggro from everyone else in the process, allowing you a relatively safe excape. Even shadow beasts can only reach you with their smoke, which you can mostly ignore unless you are at the very edge of death. The only real threat to you on top of a freshly built derp tower is spiders. If you see spiders approaching during this age, you generally want to disengage any fight you happen to be in, and fight them without any other interference. Their wonky hitboxes and speed make them a threat you don't want to mix with any others.

About wheels and carts...

You've probably noticed that the grear and millstone show in the advancement tree after the wheel and alongside the cart. You may be tempted to reinvent the wheel here and get some horse-drawn carriages to ease travel and transport of items, and I HIGHLY recommend that you DON'T. I've never been able to get the wagons to work, and wheels have no other use. Maybe I was doing something wrong, or had some kind of keybind conflict, but they aren't necessary, require the luck to find a horse, and you can get to the next age just fine without that branch being active. If you want to give it a shot, go for it. But don't say I didn't warn you.

Spotting legit rocks in the wild:

Have you ever REALLY looked at the rocks that you pick up off the ground? Have you ever listened to them? Tried to get a feel of what it's like to be them? Maybe you should. It's far too easy to take the simple stones you come across on the ground for granted. The reality is, many of these rocks are anything but mundane. If you've played sevtech much before, you'll know why. If not, you will soon. For now, you'll want to preserve some rocks, while others can be used without worry. Telling them apart is easy, and there are a number of ways to test them. If a rock pases any of the following tests, they will also pass all of the others, and you should leave it be. These rules apply for ALL ages, not just the early ones.

1: You can stand on it. Legit rocks can be stood on, with a noticable change in elevation. Mundane rocks will be "passed through".

2: It is underwater, with an air bubble around it. Which is also useful if you are trying to walk around on the bottom of an ocean for some reason. It won't protect you from the wildlife, though.

3: It talks with an accent. Legit rocks make dirt sounds when punched. You want to be very careful testing like this though, only very fast clicks with no tool should be used, as they aren't very sturdy at all. Mundane rocks will pop off the ground instantly. But honestly, there's no reason to test rocks like this. just try stepping on them.

Is the bear claw paxel worth making?

Usually. It's not like you'll ever use the claws for anything else. You might come across bears during your nomadic time, and you might not. You might kill 2 bears and get enough claws, or you might have to kill seven. You might want to prioritize other items like food or skins in your inventory. You might decide that sticking your nose into the blood feud between step wolf and brown bear isn't worth the danger. And all of these are valid. but, if you decide that you really want that paxel to clear up inventory space, there's something you should know. The bear claw paxel is a fickle beast. It is definitely the best excavation tool you will have accesss to for some time, being about on par with a bronze tool in terms of dig speed. But there are some blocks that it just doesn't like. It has trouble with nonstandard stone like limestone and marble, digging them very slowly and destroying any potential drops in the process. It struggles with some complex progression blocks, and seems to be allergic to some kinds of tree. You are going to want to keep standard flint and stone tools in your back pocket in case you have to deal with these, defeating the idea of the paxel being an all in one tool. But, it cannot be argued that it has more durability and speed than any other tool you have, and makes a decent weapon as well. If you decide to make a paxel, (and you shouldn't go out of your way to do so), then do yourself a favor and NEVER use it on ANYTHING valuable, or you might just end up losing it.

Once you set up a home base, use your Nature's compass to search for the biome you're already in. This should cause it to point to the spot you're currently standing.
There aren't any ranged enemies in this age other than baykok. The advancements tree might try to tempt you with the promise on an early ranged weapon, but do not fall for it.
You can make tiki torches by crafing a lit fiber torch with two sticks. They are worth it.
If you stick to using vanilla wood types when possible, then stripping each log's bark before use will give you enough bark to last several ages.
Make a horse chopping block as soon as possible, and set up woppers leading into and out of it. You will save so much time.
If you don't need the horse press now, then you still will later. Just make it now.
None of the 3 horse machines actually check the blocks immediately around them, meaning you can group them all up next to each other in a 2x2 area and they will operate just fine.
If you have your horse machines near your livestock or farm, the cows tied to the machines will break their leads to get the wheat. Keep them separate.
Oh yeah, cows are by far the best animals for horse machines.
Keep the whole walking area of animals working horse machines within the same chunk. You can use f9 to see chunk borders easily.
Your farmland doesn't need to be near water. Your crops will grow faster if wet, but the farmland won't change back to dirt if there are crops planted.
Don't turn all your animal skins into raw hide. You can use those to make gear easily in the next age.
Buffalo meat is ABSOLUTELY goated, and its massive amount of saturation will be very helpful in the next age.
The buffalo dance will only turn 2 cows into buffalo at a time, but you can do it more than once to get more buffalo quickly. Just don't change ALL of your cows.
Adult buffalo are so much bigger than young buffalo that when they grow to adulthood, it can cause them to suffocate when their heads get stuck into solid walls. Always surround your buffalo with walls or fences to avoid this.
If you want to leave the darklands ASAP, make a garden trowel and a fisherman's strainer. Eventually it will catch vines, which you will want for the near future.
It's worth repeating: if you can't hit the opposite shore with a thrown rock, THEN MAKE A RAFT.

As a final note before the mental rush of making a couple porcelain boxes knocks us comatose for several seconds while all the gnomes come out of hiding and swap out some of the stones for shinier stones, I'd like to present the humble grill with the "universal champion of usefulness" trophy. Put down a wopper going into it and a flame wopper under it, and that grill will passively cook dozens of stacks of anything a vanilla furnace can while never requiring any fuel, power, or supervision, regardless of what age you've reached, and without danger of setting nearby wood blocks on fire. ANY base you make should have a setup like this. Maybe even two, despite only one being needed to handle any demand you have for cooked items. The utility of the grill rivals that of the ender furnace, an expensive item unlocked in the space age after going to the end. It really is THAT good.

You awake one morning and look around your humble home. It suddenly feels small, and less comfortable. Maybe there's something in the air? You look toward the sunrise and take a deep breath. No, the air is the same as ever. Your eyes continue to wander, before settling on something you hadn't noticed before. You realise that nothing about the sky had changed, but something in the earth definitely has.

Notice annything different? Some of the rocks around your base might've changed a bit. Your path here might diverge somewhat depending on your choice of habitation, and I will assume for the sake of the guide that you are going to leave the darklands, although you are under no obligation to do so. I still recommend reading every section though, as even if you are staying put, you're going to want to do some adventuring from home.

Your main objective in this age is to create the astral tome and the luminous crafting table, but doing so is more complicated than you might excpect, especially if you've played with astral sorcery before. But before we can collect the pure, cold light of the stars, we must first learn of the gods that sleep beyond them, and conquer the darkness of the earth. Your destination is set, but you'll have to make your own road there. Whether that road is long and narrow through unfamiliar lands, or winds around and around the same familiar turf is up to you.

This age gives you access to storage crates. Crafted as a chest in a chest, they act like very cheap shulker boxes, and can be shift-clicked to pick up like a normal item. making use of them will MASSIVELY increase your effective invenotry size, though using them is cumbersome. With their help, you can fit an early-age base into your pockets with ease, leaving plenty of room for goodies you find while travelling. Building them with different types of wood is helpful for keeping things organised, if the option is available to you. These items alone can enable a nomadic style of playthrough, though as ages progress this will become less of a possibility.
Are you a minmaxer who won't be satisfied unless their base location is Absolutely Optimal? Astral sorcery features a "hotspot" mechanic, in which some places are more favorable than others, with no way to tell the difference without a fosic resonator. You won't be able to get your hands on this item until early in the next age, so if you really want things to be perfect, you might want to keep your decor to a minimum until you can find the perfect spot. Details are in the "juicing stars" section of age 2.
As ages progress, you will unlock more and more means of travelling quickly. Right now your best options just let you run faster, but the future will bring means of bounding across the landscape with ease, portal hubs, endless flight, and instant travel gateways. You don't need to be limited to having just one base of operations.
You now have the means of spawning in passive animals in whatever area you see fit with the alicio tree, so don't feel limited by the availability of any particular animal from vanilla minecraft. With it, you can set up a fully functioning base just about anywhere... even places like the abyssalcraft realms or the hunting dimension. Check out the "new home" section for details.
Speaking of the hunting dimension, you now have access to a customisable dimension for fighting hostile mobs, meaning that you no longer need to stay in the darklands to collect shadow gems. Check out the "New Home" section for more details.
Are there not any visible ores near your home? That isn't too big of a deal. Bring a few empty storage crates with you on expeditions, ore veins are typically large enough to fill one of them, and one crate full of copper tin or coal is enough for 25 people to get through age 1 with extra to spare. All you need to get by is one vein.
Have you found dark oak Yet? Or a shoggoth lair? These things are no longer optional, and you cannot progress without them. If your luck is particularly poor, you will have to search long distances to track them down. You might find it worthwhile to pack up your base and return to the noadic lifestyle until you've collected what you need. Check out the "far-flung" section for more details.
If you've decided to move house, you may have a destination in mind. Nature's compass won't be any help getting you there (without doing some cheeky config edits). Check out the "far flung" section for some tips on getting to where you want to go, and whether you modify nature's compass or not.
Even with full nutrition buffs, the water is still dangerous! If you can't hit the opposite shore with a thrown rock, THEN MAKE A RAFT.

Before you dive into age 1 proper, there are some quick steps I strongly recommend you take before heading out for the mines. To start it off, it's time to make a very important choice: Does your outfit go better with red or green? It's time to finally craft your second lifelong companion in sevtech, the slime boots. At this point, you have the means to make green slime and coagulated blood. You'll need 10 slimeballs worth of either one to make the shoes, which can be sourced from either 40 rotten flesh squeezed through your melter or 40 rice mashed into paste. (You turn the rice slime into green slime by crafting 9 into a slime block and then breaking it apart again, the odd riceball out can be used as-is for boots.) The choice is ultimately up to you, but you should DEFINITELY make one of them, as they grant you the ability to use slime physics.

You see, slime boots subtly alter your physics while bouncing in a way that raises your maximum air speed. All you need to do to activate slime physics, and therefore slime speed, is to bounce a single time. This can be achieved by doing a single walljump off a tree, or jumping and dropping one block below where you started. That meaty smacking sound means your boots have kicked in, and you will remain in slime physics until you touch the ground while moving below a certain speed. It's hard to qualitatively describe this speed, but you'll get a feel for it over time. For now, just keep sprinting forward and hold jump, even if you stop hearing slime bounces you will still sprint-jump noticably faster than normal. Avoid large obstacles or plants that will slow you down or damage you, these will interrupt your slime physics. Although, even if you get interupted, it's usually very easy to activate it once again.

Oh yeah, if you hadn't noticed yet, you can climb and wall jump by using crouch while pressed up against any surface. It costs hunger, but will let you scale flat vertical surfaces with surprising speed. This will be very useful for digging straight down into the earth and getting back out again (more on that in the mining section), and it will only get more powerful in the next age. But that is then, and this is now.

Now, you can make a hoe, and very easily expand your farm space. Since having a balance of food is so important, you should have some sections dedicated to fruit, vegetables, and grains. The way you go about this is up to you, but I would like to bring your attention back to the brown mushrooms I recommended collecting in earlier ages. These are for more than just fermented spider eyes of course, as I implied. Let's address this now. As your farm is right now, I recommend growing potatoes and wheat, cotton if you don't have sheep around, and sugar cane. You can add any other things you like of course, but these are the basic staples that will get you by. You can combine the bread with any meat to make tasty sandwiches, or use a strainer for fish. Generally it's a good idea to reach for the combo foods if possible, making it easier to keep your food groups topped up with minimal inventory space taken. And in my opinion, the best food for this purpose... is hearty stew.

Hearty Stew.

Yes, it requires a couldron, and it requires many different ingredients, requiring a diverse garden and keeping of livestock, and solving the problem of farming mushrooms, which is no easy task. But these are conquerable tasks, and I personally enjoy the sort of garden and base planning that it requires. Now, I'm sure you can figure out the common ingredients. The mushrooms are the tricky part. Solving it will require digging out a mushroom cave... you can bonemeal mushrooms planted on grass to grow them into giant shrooms, but only below a certain light level. There is a single light level that is dark enough for these to grow, but light enough for grass to spread, while also preventing mob spawns. Getting the lighting of a cave can be tricky, and will take some planning.

You can use podzol or mycelium to grow and bonemeal mushrooms in broad daylight. This is also easier said than done of course. I've never personally seen mycelia in the overword in all my time playing this modpack, I'm not sure if mushroom island can even appear in the overworld. But you can find podzol in mega taiga biomes. I'll put more details on how to find these in the "far flung" section. For now, let's assume you've found it (which isn't always guaranteed) and talk about how to actually collect it, because we can't silk touch anything yet. Luckily, we have the poor man's silk touch: stone bit chisels and bit bags. You can scoop up two full blocks per stone chisel, and fit enough in your bit bag to make a considerably sized farm. Even better, podzol isn't reverted to dirt when things grow on it. This stuff can't be created in this version of minecraft though- that came later than this pack was made. So treat these carefully, they are a non-renewable research. It's worth searching for podzol, giving you easy access to food that fills 3 food groups with excellent nutrition. But you probably shouldn't torture yourself over it, considering that you can do something similar with a shady cave.

Whatever you decide to do though, don't leave too early. You might not have much more use for darkland wood anymore, but you'll be kicking yourself if you didn't think plagued flesh was important enough to carry with you, and you might find yourself wanting a large amount of shadow crystals later down the line. At the very least, you'll want five or so on-hand to craft more flame woppers and make an energy pedestal. While you're at it, make some creeping moss before you go (you did get vines like I suggested, right?) and bind it to the dark lands. You only need one, and can propagate more from there. Feel free to snag more samples of other biomes as you go, but make sure you don't accidenally overwrite all your darkland moss.

You can craft an antique atlas now. Do It. Now. Do It. Make more leather if you have to, I don't care. CRAFT IT NOW.

With some prep work out of the way, you're ready to get walking. What's yor purpose for this? The exact details depend on your luck and your priorities. Maybe you're looking for metals, or the more elusive rock crystal. Maybe you still haven't collected the monolith stone you need to make outer god statues (that's what they're actually called, go read the classics), or the dark oak wood needed for the blank teleporter. Maybe you think that growing mushrooms underground is lame. Maybe you figured out how to move water with the liquid bit tank, and need more clay for aquifers. Maybe, just maybe, you're a cheeky blood magician who read ahead and saw that you can use sea lanters to make a tier 3 blood altar, and want to get your hands on some overpowered loot early. (Don't do this, you are wasting a lot of your time. Don't worry, we'll get to why at the start of the next age.) Or maybe you're like me and are sick of how grey the sky is in the darklands. Regardless, time to move. Grab some storage crates, stick your feet into some comfortably slimy boots, and get bouncing. I'll note some places of interest after this next aside, and why you might want to visit them.

The SevTech Biome Heatmap

You may or may not have noticed in your rather limited travels so far, but the terrain generation of sevtech isn't quite as random as you might be used to. You can think of the worldgen of Sevtech as the sloppiest plaid pattern you've ever seen: Travelling north/south will have you cross stripes of temperature (hot, warm, cool, cold, cool, warm, hot) while traveling east to west will have you cross stripes of moisture. (wet, normal, dry, normal, wet). Most biomes fall into these descriptions as logic would dictate, and I'm not going to list them all here. Just the ones I personally find the most compelling to visit.

The Darklands (You Are Here)

The darklands are all cool with normal moisture, except for the plains, which are cool and dry. You know why it's important to be here, though you llikely won't have any reason to come back unless you planned poorly and need more shadow gems or coralium flesh.

Roofed Forest

If you don't have the luck of stumbling across a darkwood hut, you'll have to get darkwood from the source. These biomes are warm and wet, and honestly not particularly common. good luck, may the odds be in your favor. You might be travelling for some time before coming across one. Also, they're just cool places to build, what with the thick canopy and vivid colors.

Mega Taiga/Redwood Taiga

These biomes have wood aplenty, plenty of podzol, and bolders of mossy brick. They also tend to have very interesting hilly terrain, which makes them a personal favorite of mine. They are cool and wet.

Coralium Swamp

These places hold all kinds of neat and interesting things, but you're mostly here for coralium pearls (also found underneath oceans, but much less common). If you see a ring of glowing runes stone with a shrine in the center, mark that down as well. if you have plenty of food and good nutrition buffs, you might want to hang around until you can create a treasure to hold onto for later... If not, wait until you're more prepared for a fight. You can also find those in regular swamps.

Ice Spikes

This one is a bit of a lower priority. One of only a few cold-wet biomes, you tend to find these far more often than in vanilla minecraft. You may have noticed that slime speed lets you travel at truly unreasonable speed across ice, so packed ice might let you build highways if you feel so inclided. Of course, by the time you'll have silk touch to collect it, you'll have faster and less laborious options right around the corner. But, while you're in cold areas, that ice does make it far easier to prospect for valuable ores across large areas. If you truly are one for the glory of the mines, you might want to settle somewhere cold.

Nature's Compass

Okay that's all well and good but I've been sprint jumping around for hours and still haven't found a roofed forest. I've crossed several moisture and heat bands trying to find it, and all I get are these damned useless menril forests and autumn woods. I'm starting to suspect you're pulling a fast one on me here, with how these biomes seem to be out of place and sprawling wildly into regions they shouldn't be. Just tell me how to get the compass working so I can be done with this.

I did say that the generation was the sloppiest set of plaid stripes you've ever seen, right? I meant it. But yes, at this point you've more than earned the right to use the tool that was specifically intended for situations like this before it was nerfed. Find your installation folder for the modpack (most modloaders have a buttor for this, and if you did a manual install I HOPE you remember where you put it) and open the config folder. In it you will find a file called "naturescompass.cfg". Pop it open with your notepad equivalent of choice, find the beiome you want to get pointed to, and simply delete it from the list. I recommend leaving everything else as-is, especialy for the other mods. You'll have to reload the modpack, but once you're back in, you will find that the compass now allows that biome to be searched for. Safe travels.

Some general travelling advice:

Keep your antique atlas on your hotbar, it's less annoying than your offhand.
Bring plenty of food. slime speed requires a lot of food to mainain over long distances.
You may notice that slime speed also lets you swim faster than usual. This Is No Excuse To Not Have A Raft on your hotbar in the case of large water crossings and sudden fish swarms. Use A Goddam Raft.
You might come across ocean monuments during your travels. Grab some sea lanterns if its convenient. if not, we have other means of getting them later. You'll want at least 4 of them. squid-enderman totems are immensely helpful when raiding ocean monuments, but trying to clear out a monument at this age is a major pain in the ass. Possible, but not worth it.
Storage crates are easy and cheap to make. Why aren't you carrying like 10 of them?
If you spot an ore vein that you need while away from home, and your prospector reads it underground, you might as well dig down and grab a stack or two of the metal. You DID bring extra storage crates, right?
Come up with a system for marking waypoints. Use different icons for different purposes, and don't just delete a waypoint to an ore vein because you cleared it out. recreate the waypoint as an empty mine. You may find it convenient to go back to these later for easy access to valuable stone variants.
Did you find a place you want to call home? feel free to settle, but don't unpack everything right away unless you change your mind.

Maybe you've ventured far, maybe you haven't ventured much at all. Either way, your old space is insufficient, and it's time to build anew. What makes a home in stage 1? Let's consider what we'll need, and what our more exotic options are.

For Age 1 to go smoothly, your base will need:

A decent farm space with animals. You'll want to maxe out your food buffs, and meats are powerful healing items for this early age.
Space for your horse machines Where they don't cross chunk borders (remember, use F9). You'll get constant use out of these for a while longer, especially the press.
A 3x3 space for a blood altar. You'll need it to be tier 2 before the age is even half-over.
Enough space for your smelting setup. How you do this is up to you, I usually just have a single melter and heater with a table on one side and a casting basin on the other and push everything throuhgh that one melter. But if you are so inclined, you could add a second melter and allowing tank. It's overkill for what you need and can be replaced by an objectively better option soon-ish, but it is fun to do.
Storage. Make plenty of it ahead of time, and understand that you will need more of it. It will be a long time before you can make highly compact storage.
Drying racks are very useful, and it'll be nice to have at least 8 of them around. Not to mention they are convenient storage for your totemic ritual instruments.
A hunting dimension portal. This is how you will bring other biome loot straight to your doorstep.
Enough space exposed to the sky to fit at least one "gateway" place of power (check your nectronomicon) near a power pedistal.
A 5x5 floorspace somewhere to safely place a portal to the beneath.
A 9x9 floorspace somewhere that doesn't cross chunk borders to make a ritual circle for Abyssalcraft
(Seriously, DO NOT cross chunk borders with this. The main altar and auxillaries often disconnect from each other if you leave the area, forcing you to bust them all down and build it again.)
Space for a water wheel, with a millstone below and sawmill to the side. The clay wheel can be temporary.
Space for growing trees.

If you plan to stay here long term, you might also want to plan for:

A notably larger space for your blood altar, open to the sky. In the next age you are likely to get access to an item that makes blood magic very fast and basically free, so there's no reason not to dig in to the powerful tools it brings.
Large open spaces exposed to the sky. To get the most out of astral sorcery, you will want an iridescent altar (13x13) and an attunement array (17x17) which must see the stars. (Having the altar at a high elevation will also improve it's capabilities, so you may consider building a large tower.)
A place for a large smeltery.
A flat outdoor space nearby for a wide, huge tree.
An easily accessible 2x2 pool of water that can be walked on all sides and corners.
Space for a spaghetti of axels coming off of a few more water wheels, and an area of only fireproof blocks nearby one of them.
A tiny and absolutely guaranteed safe panic bunker for you to AFK in. Guard it with the possibility in mind that mobs occasionally glitch though 1 block thick walls.
A 7x7 space to eventually place a gateway.
Ample space dig down, or plenty of open space around to place large buildings.

But enough of being practical. Let's get exotic.

Where can we build right now just to flex that yes, we do indeed live like this?

Ocean monuments

With a lot of preparation, you can conquer ocean monuments with squid and enderman totems, being SUPER careful not to be obliterated by guardians in the process. Only do this will max nutrition buffs, and go into it knowing that a few moments looking away from your screen or taking a wrong turn in the interior maze could end your life. ESPECIALLY on hardcore difficulty. Once you can cleared out the elder guardians, you can use their sponges to drain the monument and reshape its interior to your own designs, which will make for a fun puzzlebox experience of figuring out where everything you want to include will go. There are sections of the monument tall enough to grow regular trees, including the alicio that will let you manifest animals to farm. Settling here can be rewarding if you're the right kind of person, or extremely punishing if you slip for even a moment.

Hollow redwood trees

The hard part here is finding the things. But it's always a fun challenge to hollow out a large redwood and try to fit everything you need into it. Most of your resource farming will have to happen outside the tree though, unless.... Consider growing 4 or 5 redwoods close to each other, and then connect their outsides to form one mega-tree. This can lead to a very interesting base, with a lot of potential for fun themed builds using chisel and bits. And the perfect area for astral sorcery will create itself right at the very top. This WILL be a very time-consuming build, though.

A miscellaneous landmark

There are some oddities of world generation that sevtech can spawn, like absurdly large gnarled oaks. They are very pretty, though the areas they tend to appear in tend to be kind of bland. At least you won't have to fight your own hubris to settle near one of these, but finding one in the first place is a game of chance you are unlikely to win.

The hunting dimension

Yes, you can settle here. With a blood lantern sigil, alicio tree, and plenty of wood for ocelot totems, it isn't nearly as hard as the heavily damaging and healthy natives might make you think. Their spawns do respect light levels, and astral sorcery does work here. It even has starlight hotspots. Just be aware that despite it always being dark and the sky not moving, this area does experience a day/night cycle, and weather still occurs. Also you're gonna want to build very secure walls, all around, and probably several panic bunkers. This place is very dangerous, and your hubris might be the end of you. Make ample use of totems and their wide range of benefits, and enjoy that customisable mob farm you undoubtably had in mind when considering this option.

The Beneath

This is the masochistic option. mobs here are strong and have lots of health. It'll be a LONG time before you can even consider doing astral sorcery in here. If you leave even the slightest shadow anywhere in your base after this age, you'll be constantly be hounded by obnoxious shadow creatures who just want to make wierd noises in your ear and jumpscare you. Sure, okay, you use bit bags to smuggle grass and water in here. Sure, you can grow an alicio tree for livestock. Sure, you can eventually use multiple floating celestial stones in their fancy starlight fountains to satisfy your iridescent altar. I'll even give you the concession that the Beneath has ores that aren't found anywhere else, and its easy to spot ores embedded in the walls by using enderman totems. But like... Is any of that really worth it when you have some annowing ghost poking at your eyes and grumbling at you constantly? to be obligated to light up every single square inch of anything you might consider touching at some point, and STILL need to leave your base to attune items or stack wild amounts of enchants on an item? I guess you're the only one who can answer that for you. But I know my answer.

And much more, coming soon.

You may still be unsatisfied with your options. Fair enough, yknow? The next age has another huge expansion of potential homes waiting for you. Maybe one of them will strike your fancy. Even if you've already found a place you enjoy and put a lot of work into, your vacation home can be just a quick step away with the help of some starmetal and marble...

Rock and stone. Anyways-

A full guide on how to strike the earth: Aka: the finer points of mining in sevtech

I've said it plenty of times. Bring storage crates. Bring more than you think you'll need.

We both know at this point that ore samples on the surface indicate a vein down below. These ore veins spawn at a certain Y level, and if you're on high-elevation terrain (or the ore is just particularly deep), how do you know where to dig?

The secret lies with your F9 key. Use it to see whe borders of chunks around you, and the centerpoint of your current chunk marked with yellow. A surface sample indicates that a vein of ore generated in the chunk that the samples occupy. Even if the vein leaves the bounds of that chunk, the samples will not follow it... And these veins are almost always generated overlapping the center blocks of the chunk. Knowing this, you can often be confident that digging in one of the four center squares of the chunk will lead you to ores. This even works for small-vein ores like rock crystals. I'd keep my prospector around just in case you need to poke around at depth, though.

You may remember I mentioned earlier that we would be digging straight down, breaking one of the oldest rules of minecraft. Believe it or not, theres a simple precaution we can take to do this relatively safely. Dig one block, then sneak on the edge of a neighboring block and stand over the edge between the two. You should be able to dig both blocks now, by alternating tigging the inside face of one and the top of the other. Sevtechs large cube particles will fall and land on the blocks below, and should breaking blocks beneath you lead to a dangerous fall, you will see the particles of the broken block fall away and have time to react before breaking the other block you are standing on. This does require you to be paying attention, of course.

What about escaping? you can use wall climbing to get out of a mineshaft you dug, but if it's a vein near your home that you might want to dip into repeatedly for smaller amounts of ore, you should use that fancy knife that you strip bark with to carve ladders straight into the walls. this will be slower the first time, but with fast ladder mods active you will save a lot of time on later trips.

Don't feel pressured to dig out entire veins all at once in this age. Your tools are slow and break easily. The next age will give you dreastically better options for excavation.

Wait, what about coralium pearls? I've never seen a surface sample for those. Correct, and you never will. These generate more like normal minecraft ores, but only under swamps, oceans, and coralium swamps (Though they are noticably more common in the swamps). Run around and make good use of your dowser to track these down. When you find some and dig them up, make sure to poke around the area you just dug out. You can often find another vein within dowsing range.

A few things I wanted to mention but didn't warrant their own sections.

Snares suck. To do what you need with blood magic, you'll need 1 demon will of any quality, and one demon will of at least 1 quality. (Though,above 2 is better.) You might get this in 2 snares. You might only get it after 15. There's no tricks to make this better. Good luck.
You should absolutely invest in getting a blood lamp sigil. This will take some time and a lot of dead mobs, but it is absolutely worth it. This will also result in you having a sentient sword that hits above its weight class during this age, which is very nice. Once you have the blood lamp and an ample supply of LP in your network, just drop your sacrificial tools in a chest and don't bother with them for a while.
Having a blood lamp sigil will make finding ores in the beneath far easier. I recommend bringing plenty of wood for enderman totems- Use them to spot your desired ores from a distance, and then stick lights on them with the sigil so you can easily keep track of where they are.
If a fight seems dangerous, just run away. Hell, if a fight seems inconvenient, just run away. You can come back later, and the beneath and hunting dimension mods really aren't messing around.
Use aquifers. They're very convenient in any age of the game to have free water.
If you place water somewhere using bits, IT WILL NOT FLOW UNTIL AN ADJASCENT BLOCK UPDATES IT. This is especially important when using water to descend into the lower layers of the beneath. If you don't update your water before jumping in, your will find your descent happening much faster than expected.
You might as well just make the clay bucket now. You'll want it immediately upon entering the next age to collect lava, so you might as well get it out of the way before the skeletons start trading trumpets for bows.
Building places of power isn't exactly necessary, but it is preferable to the wrath of the outer gods. Unless of course, you have truly nefarious purposes in mind.
Don't try to loot statues from shoggoth lairs. it isn't worth the time or effort, not to mention the high likelyhood of being boxed in by spawning shoggoths.

You've worked hard to get to this point, and your efforts are bearing fruit. Working the earth and its products has become second nature. But couldn't there be more? More fantastic places to roam, brighter colors to work with, more shapes to cast. You look up to the stars, and how their light reflects off of the polished surface of your luminous table, the peak of your current abilities. Perhaps if you reached a litle higher, you could find these things... Perhaps, if you dug a little deeper, you could find the tools to do so.

Welcome to age 2. This is where your possibilities really open up. If you've done some preparation before making the transition, then you are in an excellent position to quickly advance through the early steps and equip yourself against the rising threats that lurk in the shadows of age 2. If not, then you might want to hop to it. The mobs of the night now have proper weapons and armor, and the hunting dimension in particular is full of life-ending threats. If you thought I was making stuff up about the difficulties of settling in the beneath, you're in for a rude surprise. To keep your priorities straight, let's lay out the things that you NEED to do, the things that I think you SHOULD do, things that you might WANT to do, and things that you should probably NOT do.

Things you MUST do to progress the age:

Improve your luminous crafting table to the next tier, and create starmetal. Eventually, it will need to be upgraded again.
Kill one enderman. If you're unlucky, you may need more. This is to craft a resonating wand, a necessary item for activating astral crafting.
Mine gold, lapis, rock crystal, and iron. The gold will be necessary for making metal casts, which is needed to create a pearl from ender dust. The iron ore chunks, rock crystal, and lapis are needed to make starmetal.
Gather lava to enable the working of iron.
Explore the twilight forest and kill several powerful mobs to get fiery blood or tears, and gather a handful of steelleaf.
Aquire pistons. It's far easier to just steal them than to try and craft them.
Dip into the betweenlands and sniff out a red middle gem and some Octine.
Cobble together your assorted goodies into a coal engine to advance.

Seems simple enough, right? It doesn't look like a very long list. And honestly, it isn't. The steps to complete this stage are relatively few, and the majority of your time will be spent on the "explore the twilight forest" part. Keep to the straight and narrow, and you'll be in and out of age 2 pretty quick. Either by moving into stage 3, or being sent back to stage 0 in a coffin. You'll also be missing out on the wide breadth of possibilities this age has to offer, because this is the age where players become demigods.

Things you SHOULD do to make the best of the age:

Create tinker's tools. Stone is fine to start with, but you should upgrade the set to iron when possible. More details in the "Tinkering" section.
Create a longsword and shortbow with ample arrows. More details in the "Age 1 prologue" section.
Make a metal plate cast.
Create iron armor.
Upgrade to a celestial altar early.
Keep crafting constellation papers until you have 5. A telescope will be adequate to discover these.
Create and activate an attunement altar. Be careful you don't step too close until you've decided which is your favorite... Although I do believe there is an objectively correct option. More details in the "Written in the stars" section.
Create a decently statted floating crystal. Maybe a floating celestial crystal, if you feel so inclined. This will require the stone to be attuned.
Attune your mediocre celestial crystals and use them to gather starlight. They will last a long time, and production can be boosted massively by linking a floating crystal.
Create a fluid hopper and a very tall clay barrel to automatically empty the lightwell.
Dip into the Twilight highlands and snag some podzol if you don't have any yet. You'll want to be quick about doing this to avoid melting.
Are you a completionist collector? There is missable content in the twilight forest. More details in the "Twilight zone" section.
Camp out on hermit crab spawners until you have enough knightly fragments to upgrade your favorite tools. Knightly metal far outranks iron.
Thoroughly loot ghast towers. Collect as much Steelleaf, experiment 115, and shiny cyan rocks as you can. A stack or so of redstone would be nice as well. DO NOT EAT THE EXPERIMENTS.
Consider changing your tool's extra parts to steelleaf for the synergy trait. More details in the "Tinkering" section.
Visit the betweenlands and close sevtech once it loads in the intial surrounding chunks. This will fix a memory overdraw issue with the first visit.
Don't stay in the betweenlands for longer than you have to. Grab octine and middle gems, make a purifier, and get out. More details in the "In Between" section.
Replace your melter setup with a proper smelter.
Craft a lens with decent stats and a pink colored lens to place over it. Place it beside your blood altar and connect a floating crystal to it. Let the blood flow.
Upgrade your blood altar with those sea lanterns you might have collected before, in place of glowstone blocks.
Reorganise your base. Make things nice and cozy, replace your storage with gold chests. Do some decorating, maybe. Once you've sure everything is where you want it, make a cake with redstone frosting. Details in "The twilight zone" section.
reorganise your waterwheel setup, now that axels are cheap. Leave extra space for growth.

These are listed in roughly the order I recommend tackling them in, as some are prerequisites for others, or will simply be much easier once others are completed. Doing these will put you ahead of the curve as you move into the next age, with ample resources for empowering yourself and building up your base. None of them are necessary, and some of them are more laborious tasks that you can skip if you really feel the need. The next section is even less necessary, a mix of things I recommend you do for the experience, or to truly put yourself over the edge in terms of what you are capable of.

Things you might WANT do to milk everything you can from this age:

Collect a few slimy bones from the betweenlands and transformation powder from skeleton druids, and make a portal key to progress into the abyssal plain. See "into the Abyss" section for details.
Defeat the abyssal dragon and progress into the dreadlands.
Upgrade to an iridescent altar early.
Keep crafting constellation papers until you have all 16. You will need an observatory to get all of these, and the later constellations will require some patience and diligence to discover.
Consider carefully how you will be spending your 30 starlight perks, and consider which of the outer 4 is worth your investment.
Create a set of starlight mantles with your favorite attunements and keep a backpack to carry them with you.
Create a routing network with blood magic to (mostly) automate blood crafting, or atuomatically manage storage.
Simplify your liquid starlight storage with a massive blood tank. Simplify your anything storage with massive blood tanks. Make a few extra, in preparation.
Fully conquer an Ur-Ghast tower and consider moving into it. The resources contained within are valuable and largely unique, the elevation makes the top idea for sastral sorcery, and the spacious interiors will provide ample space for industrialization. The lack of spawnable space around it offsets the higher resource cost of the twilight forest and makes mob grinders easier to build.
Loot the low-grade charcoal that is found in ghast towers, before the next age turns it into something much less valuable.
Fully conquer the twilight forest and collect the ultimate reward. Consider taking the castle for yourself and turning the underground cages into a zoo of strange and dangerous creatures. See "The Twilight Zone" for details.
Create a refraction table and experiment until you master starlight enchantment.
Explore under the large, round hills of the twilight forest and collect some glowy powders.
Take on an ocean monument and loot some sponges to make a squeaky pick. I recommend using sponge as the handle material.
Make a vicio-resonating wand to go with your vicio starlight mantle.
Use blaze rods looted from the minotaur's maze to create an alchemy table. It will save you a lot of time making leather and obsidian in particular.
Backpacks. I recommend the gold ones from the iron backpacks mod. They cost more metal for the same storage space, but also FAR less leather. You can install upgrades on them... later.
Create a satellite base in the abyssal plain. The place has a cool and unique style. Just don't plan to get comfortable there, a mini dragon that can pass through blocks occasionally spawns in to harass you, and it is deadly if you aren't prepared. Yknow what? Maybe just bring some of the soil and stone back with you for decoration.
Craft some brewing barrels and a crushing tub and get brewin'. Perfecting your drinks is a fun side project, but the benefits are overshadowed by nutrition buffs.

There is probably a "best order" in which to take these on, but I didn't bother ordering them beyond my train of thought writing them down. The final section are things that I recommend you avoid doing. They are either really tedious, actively harmful to your chances of survival, or the reward is not worth the investment unless you're a completionist.

Things you should NOT do, even if they seem kinda cool:

Build a base or stay in the betweenlands for an extended period of time. I love the betweenlands, but this modpack really does it dirty. More details in the "In Between" section.
Do much of anything in the dreadlands. This dimension is ugly as sin, the standard mobs are annoying but not difficult to defeat, and the keeper of the key to the next dimension is boring right up until it obliterates you with an untelegraphed instant-kill attack. Taking this thing on isn't worth the risk of losing your hardcore world, I have no advice for avoiding death, and its BORING. This is where I used my first recovery in my hardcore playthrough, after losing several other runs here.
Continue into Omothol and fight jah'zar.
Reassemble jah'zar's staff. I agree it looks cool as hell, but once you have it, there's no reason to do anything with it and the assembly is TEDIOUS.
Create coralium or dreadium tool parts for your tinker's tools. Sure, they are statistically better than your other material options and do more damage to mobs. Those mobs are almost guaranteed to infect You right back afterward, and coralium/dread debuffs WILL kill you. I lost one run to this, after reflex-striking a zombie in the underneath with my coralium pick. Also the gathering of materials to make these is either very tedius (dreadium) or extremely tedius and also running the risk of trapping yourself in a lava-filled ravine while a mini-enderdragon phases through the walls to attack you.
Create coralium, abyssal, or dreadium armor. See above. They do come with some cool extra perks, but nothing you even remotely need, and definitely not worth the hunt for liquid coralium ore.
Create the final tools of abyssalcraft progression. Yes, they are arguably the best tools in the entire modpack. No, they are not worth it.
Craft shifting stars while planning to attune to vicio.
Use rock crystals when celestial crystals are an option. See "Written in the stars" for details.
Create rock crystal tools. They're nice, but the upkeep isn't worth it.
Break the basalt monoliths found in the twilight forest. They will become easy obsidian later.
Fight an enderman unprepared.
Fight a small enderman, EVER.
Pick a fair fight with a towerwood golem.
Loiter near a towerwood golem spawner.
Assume that your gear is good enough to protect you from a towerwood golem.
Assume that your gear is good enough to protect you from a tall goblin knight.
Take off your slime boots.