Ace

I think things would be very complicated bc of his role in making the absolute, and it would be hard to see why he'd even join up with the party.

Gortash would probably need the astral thingy. Shadowheart has it. So he'll need shadowheart. Lae'zel makes for good muscle, and while he'd prefer durge he's clearly out of it so he'll take Lae'zel for now. Gale is just there. Why not? And then Astarion is on thin ice but durge seems to like him even after getting threatened with a knife so fine. And then it steamrolls and now he's got everyone (sans Karlach maybe? He'd either have to kill her or put all his effort into convincing her to side with him and not kill him in his sleep.)