CurseForge · Minecraft mod
Pyrellium
The vanilla+ nether overhaul
Quick answer
Which Pyrellium release should I use?
pyrellium-0.4.3-1.21.1-neo.jar targets 1.21.1 with NeoForge. The project page does not say whether this file belongs on the client, dedicated server, or both. No extra mods listed for this file.
Where it goes
Is Pyrellium required on the client, server, or both?
The project page does not say whether this file belongs on the client, dedicated server, or both.
The source does not explicitly classify this release as client-only or server-only.
What else does pyrellium-0.4.3-1.21.1-neo.jar need?
pyrellium-0.4.3-1.21.1-neo.jar. Change the file and its required mods may change too.
This file does not list any required mods. Do not add a library just because a different file uses it.
We only count dependency files that match this setup. A file for another loader does not fill the gap.
Before you install it
Add Pyrellium without breaking your instance.
Built for pyrellium-0.4.3-1.21.1-neo.jar. Pick another file and the loader, install side or required mods may change.
- 01
Stick to this file
Use pyrellium-0.4.3-1.21.1-neo.jar. It targets 1.21.1 with NeoForge; another release may have different loader, side or dependency requirements.
- 02
Bring the mods it needs
This file does not list any required mods. Do not add a library just because a different file uses it.
- 03
Put it on the correct side
The project page does not say whether this file belongs on the client, dedicated server, or both.
- 04
Pick the file you checked
Use the “Get this file” button beside pyrellium-0.4.3-1.21.1-neo.jar. It opens that exact file at the source.
About this project
What does Pyrellium add?
The Nether has always been dangerous… but it's never been this alive.

Pyrellium is a content-rich expansion mod that introduces 9 brand new biomes, seamlessly integrated with the vanilla Nether for a natural and immersive experience. Whether you're an explorer, builder, or survivalist, Pyrellium offers new challenges and rewards deep within the fiery realm.

Flaming Forests
Discover blazing biomes, and obtain new spoils. But watch out, even the flora is out to harm you.

Icy Depths
Find chilling places where frostbite meets fire. These treacherous frozen lands are as beautiful as they are deadly.

Spider Sanctuaries
Venture into eerie caverns where intelligent spiders spin homes of silk and secrets. Tread carefully. You're not alone.

Calming hopes
Not every biome is deadly, venture into the crystal forest to enjoy lands of beauty. and take a break from the danger.

And More!
Click the image below to be taken to Bisect's website

Forge?
Pyrellium is fully compatible with sinytra connector, use that for playing pyrellium on forge.
Is this compatible with X mod?
Pyrellium was built with compatibility in mind. It works alongside all major Nether mods and fits naturally into both vanilla and modded environments.
Will you be adding more biomes or features?
Pyrellium is currently in beta, this means more features are on the way. Adding more biomes itself will be unlikely, but stay tuned for new mobs, items, and other features.
Hey this looks a lot like Lankasters Nether.
Yes. Pyrellium started as Lankasters Nether, but eventually grew to big to be just a datapack, and it was decided to switch over to making a mod. Lankasters Nether is still available as it's own project for archiving purposes, but it is recommended where possible to use Pyrellium instead.
Project description from CurseForge.
Pick your setup
Pyrellium by Minecraft version and loader
Choose the version and loader you play, then open the matching release.
1.21.11
1 loader build1.21.1
2 loader builds1.20.2
1 loader build1.20.1
1 loader build1.20
1 loader buildCheck the dependencies, then try the file in a copied instance before changing a world you care about.
Recent files
Pyrellium versions and loaders
pyrellium-0.4.3-1.21.1-neo.jar
10 Nov 2026
pyrellium-0.4.3-1.21.11.jar
10 Nov 2026
pyrellium-0.4.3-1.21.1.jar
10 Nov 2026
pyrellium-0.4.3-1.20.1.jar
10 Nov 2026
pyrellium-0.4.2-1.21.1-neo.jar
6 Nov 2026
pyrellium-0.4.2-1.21.11.jar
4 Nov 2026
pyrellium-0.4.2-1.21.1.jar
4 Nov 2026
pyrellium-0.4.2-1.20.1.jar
4 Nov 2026
pyrellium-0.4.1-1.21.1-neo.jar
8 Oct 2026
pyrellium-0.4.1-1.21.11.jar
5 Oct 2026
pyrellium-0.4.1-1.21.1.jar
5 Oct 2026
pyrellium-0.4.1-1.20.1.jar
5 Oct 2026
Looking for an older file? The official CurseForge project page is in Resources.