Are there any more named NPCs getting around that have a dark side like the Markarth cannibals?
Now strike Nazeem down and take your place at the Jarl's backside!

I'm kinda' tired right now and the list is still in my head for now, but
Erikur is another one that's one it that I don't think I've mentioned.
Olfrid Battle-Born is another. Taarie is a little more tolerable than
Endarie (she's an alternate), because at least Taarie isn't quite as rude when she's at the counter. Yeah, the "rethink that outfit" comment is annoying, but she even says that when I'm wearing Pirate Princess' Robes (renamed Noble Clothes) or the Empress' Robes (renamed Emperor's Robes) so that one I can ignore. I wouldn't mind smacking
Degaine, but the NPCs always fight you in this game so it would end in his death - I guess I could cast Fear on him right after I smack him.

FWIW: I don't mind the cannibals in Markarth too much - live and let live kinda' thing - as long as they don't bother me or try to eat Muiri (wife in my chick's game).

Make no mistake: I killed
Eola on both playthroughs, but that was mainly because she was trying to convince me that I had a taste for human flesh: "Btich, you don't know me!"

Edit:
...but the Black-Briars are still essential after the Stormcloaks take over plus, is her 'free' son a Jarl candidate? Season Unending maybe?