An oddity I found while running this mod with Kathairis.  For some reason Abyssalcraft Shoggoths, Depths Ghouls, Abyssal Zombies, and Dr. Orange spawn in abundance during the night and anywhere there is shadow in the Kathairis dimension.  I'm not sure what is causing this - but to the best of my knowledge, none of these creatures are spawning in other dimension mods that we have added.  Again, not sure if this is an Abyssalcraft or Kathairis issue.  Just thought I'd bring it up to both parties just in case.

That's on their end. The mobs spawn due to their biomes being in the same Biome Dictionary group as some of the biomes they can spawn in.