World Evils

Terraria's Corruption, Crimson and Hallow in Minecraft! (It's not exactly the same)

Your world gets one of the two evils. Which one is decided by the seed and you don't get to choose. Every world is a Corruption world or a Crimson world, never both. You'll find out which the first time you open the right chest in a nether fortress.

Inside there are seeds. Plant one somewhere you don't mind losing, or in your friend's base to troll them :)

It spreads!

It spreads slowly. You'll plant it, nothing much will happen, and you'll forget about it. Then you come back from mining and your whole garden is purple and thorny.

It takes almost every block, including artificial ones.

It also keeps going while you're not looking. Walking away doesn't pause it. (There's a page in the options menu if you'd rather it went easier on your hardware. Cap it, let it throttle itself, or switch that off entirely. There's a speed slider too, if slowly isn't your idea of fun.)

What lives out there

Things that used to be something else, mostly. (Almost) anything standing on infected ground long enough transforms into whatever the infection has a use for.

There are altars in the caves, and they're the only place the Corruption's and the Crimson's gear can be made. You may also find other floating things — just be careful how many you break in a row.

Bring a fishing rod at some point, there's good fishies in infected waters ;)

The Hallow

Every world has it, and its seeds aren't in the Nether. Look in ominous trial chambers instead.

Plant it and you get the opposite of everything above. Light blue grass, trees that can't pick a colour, water that went completely magenta, and crystals in the caves doing your torch's job for you.

It's also where the mod stops being nice about it. What lives in the Hallow hits harder than anything in the Corruption or the Crimson, and it expects you to turn up in gear you took off them first. Wandering in wearing iron is a decision you get to make once.

It's got two big ones of its own. One of them you can set off completely by accident, so watch what you swing at.

By default all three keep to their own blocks and won't eat each other's. There's a switch in the options if you'd rather they fought about it.

Shaders

Every light source in the mod ships labPBR specular maps, so torches, lanterns, campfires and the rest glow properly under any shaderpack that reads them. Turn on Advanced Materials in your shader options — most packs ship it off. There's also a dedicated Solas shaders version with extra compatibility (credits to Septonius for the original shaderpack)

Extras

If you use Xaero's minimap, every mob in here has an icon for it.

All music is a cover of its Terraria counterpart, on piano. Credits to Re-Logic and its peak music.

Requires Fabric API, GeckoLib and Satin. No Melody — the music runs on Minecraft's own sound engine. If you can't hear it, check your Music volume slider before your mods folder.