User blog comment:Yoyomom/I'm done attacking Sonic/@comment-25275196-20161213021342

If there was a second Sonic rep, it has no right to be anyone other than Robotnik. Every other character in the series, even Tails, debuted in a game from Sonic 2 or later. Name one series on the roster where the second rep came from a sequel.

Other than Robotnik, it doesn't really matter who they add. Tails, Knuckles, Shadow, Silver, and maybe Amy are the most likely candidates though. Any of those would be cool (I'd like to see a matchup between Silver and Mewtwo. That would be cool).