Onslaught or Sinister
My 6* Mr Sinister was an absolute carry for me but he's somewhat fallen away with me having rank 4 7* Jean.
I've saved up all the resources to awaken to sig 200 and rank 4 7* Mr Sinister if I ever get him but I just pulled a 7* Onslaught.
I've never used Onslaught as I only have a rank 1 5* up until now but I'm aware he is a great champion.