I haven't had anything I played in last long enough to sort of be more than "neat" but I would submit
Gur-Shaak from the same campaign as Bambu's Imastrius. She was a Jungle Orc (not half-orc, full orc) Barbarian with 20 strength and 7 intelligence, and I like to think I struck a good enough balance at playing her as somewhat of an idiot without being too annoying. Plus she was just fun to play because she would trip someone, kill them in one hit, get a second attack and kill someone else in one hit on basically every turn, I think she probably had as much of a body count as the rest of the party combined (though our Druid definitely ended up carrying way more on the harder fights).
I don't think I'm 100% happy with her as a whole but my first character, Lilli a Fairy Rogue, had a pretty fun (read: absolutely ******* abysmal but in a fun way) ending, her cleric friend died while they were trying to stop some bad guy, so she literally just made a deal with a devil (thanks to a very conveniently nearby item) to revive her, and what the devil was probably expecting was to bring
her misfortune through the cursed hoard she also got, but then she left in shame and the cleric gave away all of that cursed money to poor people which means literally the entire country got hit with the curse. The bad guy that they failed to stop ended up causing tens of thousands of deaths before being stopped, the cursed money caused
hundreds of thousands with no obvious end to the misery in sight. And
then a devil came knocking at her door.