Mindfire
Istar
I haven't played AC3 yet so no spoilers! Lol. Also, even if you aren't getting Black Flag, I would definitely recommend getting Assassin's Creed 4: Freedom Cry. Originally it was DLC for Black Flag, but now you can get it as a standalone game. It's about Adewale, a former slave who becomes an Assassin and works to free slaves in the Caribbean. I know you weren't too keen on the Caribbean setting, but the slave trade narrative seems like it would have some of that gritty-ness you're looking for.