[@Maxx]i actually am thinking if  a fiend character who has something I call 'suicidal rebirth' in which he's immortal as long as he's the one that deals the final blow, and he chains the powers of the last person he touched or a meta he has touched, though the power grows weaker with each iteration until he touches that person again. Weakness would be that he needs to leave behind a body and he's vulnerable right after the rebirth. Aside from that, all weaknesses and limits that the person he copied the power from apply to him as well. A pretty messed up power, but one that would sure lead to some shocking, damn right terrifying situations. Another drawback is that killing yourself a lot generally isn't good for your mental health, so each time he does that, he comes back just a little more unhinged. It'd be a power he just discovered after taking a shit-ton of the mutagen, so he'd start off normal enough. . . for a Fiend anyway.