A character who performs evil acts, bu doesn't really know that they're evil.
So you have the guy who's bent on destroying the world and generally making everyone miserable. You have the character who isa monsterous villain, but you end up feeling sympathy for, perhaps because of a Freudian Excuse. And then you have these characters. The ones who commit actions that are dangerous and evil in the eyes of anyone around them... except for themselves. Maybe it's because of how they were raised, or other outside circumstances, but the character has no idea that what he or she is doing is causing harm or death to many others. May go into a Heroic BSOD once they learn of the consequences of their actions, possibly going through a Sanity Slippage Needs More Examples