KOS mercsFollow

Are there any zones where an ogre mercenary wouldn't be able to follow me,a "good-aligned" race? Any quest NPCs who might take offense with my merc's race?
I've been playing for many levels with this merc in Blightfire Moors,and he can follow me into Crescent Reach,but will this remain the case in other areas where his ogre-ness will be KOS?

Mercs are ignored by every mob in the game until you tell the merc that you don't like that mob. That is why invis isn't needed (and won't stick) on mercs. They don't need it.

They also cannot drown, just fyi

Anyone had any really funny merc names? I've seen a couple