Some Guy

Biography
Some Guy is the nickname of an otherwise unnamed and extremely enigmatic entity. He overlooks the events of the game for reasons unknown, but he seems to know each character in adequate enough detail. He seems to have bizarre powers of his own, namely he seems to be able to summon/'grow' replicas of other human beings, which he uses to fight.

The only real hint of his identity is that it's implied he and Tatsu Tsuyu have been involved with each other at one point in the past.