I'm betting he's Klaw. He has to be Klaw.
The Avengers seek out Klaw for His expertise manipulating the material Vibranium after getting their a$$ handed to them by Ultron. This leads them to Wakanda and subsequently the Black Panther. OR Ultron seeks out Klaw and forces him to build a new body (Ultron 2.0) out of Vibranium.
Good call man! Even if he ends up being another character it's still fun to guess like this and try to tie it together.