Good afternoon!

I tested your mod.

Unfortunately your mod does not create a separate biter faction, but simply replaces all biters with arachnids.

https://i.imgur.com/4UhXWPS.png
https://i.imgur.com/GV8MpAK.png

All good for me with Rampant fixed

I have tested several times without Rampant. For half an hour I ran around the district - solid arachnids. Didn't find a single biters.

unfortunately, I have never run it without Rampant

yeah not seeing any biters besides the ones that spawned near me, just arachnids, am running alongside Rampant fixed.

Edit: Explosive biters, frost biters, and armored bites nests aren't showing up anymore after enabling this mod and starting a new game.

Bug fixed. Now Arachnids are truly their own force, and they will fight Biters. Worked with Rampant on what I saw.