Every time you kill a Crushbone orc, your faction with the Ingido Brotherhood is going to go down - and given the likelyhood of you killing a couple of hundred crushbones, it's probably a good idea to know who the Indigo Brotherhood are.
These bad boys are Dark Elves and the first time I ran into them was in West Commons, which is west of Freeport and home to the dungeon Befallen. There are at least two dark elves there who will KOS to good races and a least one of them cusses you out in the name of the Indigo Brotherhood. There is also an occasional Dark Elf along the coast to the right of Freeport Docks (East freeport) and one in a group of Dervishes in North Ro, south of Freeport.
Good advice to all Woodies heading Freeport way is to watch out for these lads and lassies, because they'll have your head in a wink. Kidzean Gix of West Commons is particularly nasty and much harder than he cons in my experience.