Originally posted by pcdeltalink:

Far as my gameplay has shown unless they are specifically aggressive to each other by default (greydwarves vs skeletons for example) then there is no friendly fire or neutral fire in any form in this game.

Skeletons are of the undead faction, and graywarfs are of the forest, and they fight. But yes i have yet to see friendlie fire, even when a troll strikes the skeleton while a graywarf is around, nothing happens to the warf.