(Psi)SeveredHead
Adventurer
Okay, where does this leave yugoloths, who are canonically mercenaries/interlopers in the blood war.
What about clashes between demons in the abyss. In an environment where one demon cannot hurt another, it seems that the environment would become rather utopian for a plane of chaos and evil...
A DR of 10/anything isn't going to stop a demon. Inflicting permanent damage on a pit fiend was nearly impossible for a demon under 3.0 rules anyway (regeneration), but almost no one complained about that then.