Fiendish
Alignment
Any Evil
Traits
DR/good with a value equal to creature’s CR – 10 (minimum DR 1/good) |
If the creature already has DR of that value or greater, it instead gains resistance to fire with a value equal to creature’s CR – 5 (minimum fire resistance 1) |
When the creature isn’t on its home plane, it gains the extraplanar subtype |
Fiendish creatures are natives of one of the evil-aligned Outer Planes.
Source
Alien Archive pg. 151