Something terrible but giving great power, like the path of Swarm-That-Walks from Pathfinder.
I think it’s probably not what you meant, but I *hate* it when a game suddenly forces you to solo fight with a character you’ve basically built as a component of a balanced party. It’s fine if you’re a tankier fighter anyway, but awful if you’re a squishier spell caster or healer type without great damage potential. The very thought gives me traumatic flashbacks of trying to finish SWKoToR with my Jedi Sentinel.
Were you saying, though, that Larian should cater for people who want to solo in the late game with specific feats?
"You may call it 'nonsense' if you like, but I've heard nonsense, compared with which that would be as sensible as a dictionary!"