Board Thread:General Discussion/@comment-25221943-20170321020842/@comment-679780-20170321025756

A ridiculous theory of mine is that while the new character isn't dreamcast Sonic or Boom Sonic, it is a brand new Sonic unique exclusively to Sonic Forces.

'cus if you mess around with time, you'll end up with alternate realities. So if Dr. Eggman has rewritten history to conquer the world and the Modern Sonic in the game is from the default timeline, classic Sonic also being from the default timelines past, then the created timeline may have it's own Sonic.