Disclaimer: If applicable please set the openGLDebugOutput -> enabled config option from RenderLib to true and try to reproduce the issue.
-> I made it true and same crash happens

Describe the bug
nothirium crashes with celeritas

Reproducibility
Please try to reproduce the issue with as few other mods as possible. Then check one of the following checkboxes according to your results. To check a checkbox replace the space between the square brackets with an x (like this [x]) or create the issue and check the checkbox by clicking on it.

• [ x ] I reproduced this issue with as few other mods as possible installed.
• I am unable to reproduce this issue consistently.

To Reproduce
Steps to reproduce the behavior.
Please keep in mind that I most likely don't know how other mods involved in this issue work. Thus terms like "Go to dimension X" should be explained in more detail because I probably don't know how to do that.

1. download mods below
2. crash happens on initializing game

Screenshots/Videos
If applicable, add screenshots or videos to help explain your problem.

Versions
Nothirium: 0.4.7
RenderLib: 1.4.5
Forge: 14.23.5.2860
Minecraft: 1.12.2
Other mods (necessary to reproduce the bug):
_MixinBootstrap-1.1.0
[MixinCompat-1.1-1.12.2]
!mixinbooter-10.6
RenderLib-1.12.2-1.4.5
!cleanroom-relauncher-0.3.1
celeritas-forge-mc12.2-2.4.0-dev

Hardware
CPU: AMD Ryzen 5 4600H
RAM: 16GB
GPU: NVIDIA Geforce GTX 1650 Ti
VRAM: 4GB

Log File

crash report
latest log

You cannot combine Celeritas with nothirium. Choose the one that gives better performance

As Karnatour said, you can't use both mods at the same time. Both mods rework the block rendering of minecraft. You have to choose one mod and remove the other.