Can toi consider Shadow as a half-alien and half-hedgehog because his blood was taking from Black Arms and came from space?

Well I wouldn't exactly because he is still like the others but he was created in space. And before the shadow the hedgehog game, black doom didn't even exist. So I wouldn't consider him part alien. Good question though

Well, I'd say he's plus 1/4 alien and 3/4 hedgehog.