I wish there another screen after defeat him, like I and Thane carry him to the tavern then try to convince him to join the tavern.

Or how about a sex screen when player winning him ? (still carry him to tavern...)

1. He nearly killed Thane, stole and injured kids, made war between 2 tribes and you think, he will be good boy after all?)
Or you didn't read the text after losing to him? How brutal he ends with you after sex...

2.  Thane is still unconscious in the Tavern. Doppelganger took his form and backstabed Eywind (if u didn't pass skillcheck).

Don't worry, here are more chameleons (and I bet that Selye somehow involved to it). Thane said, he was attacked by several of 'em.

but you may can try to invite him to the tavern :>

that could be cool