Michael is a character in TJOC Story Mode. He is (possibly) the main antagonist, a “Phone Guy” of sorts for the other family members and the reason the animatronics escaped from the game.
He helps the others in Scott's family, as they were not needed to die in his plot to stay in the real world. He goes after Scott, and only him, shackling him to a chair and leaving him for dead in the attic, later killing him in the burning house via some unknown mean.
In the Ending, he led Scott on by trapping him in the Attic when he told Val that he was going to "help" him get out of the house.
His dialogue in the attic opener cutscene tells us that this is Michael Schmidt, as in his own words, "Being Michael Schmidt has been an incredible experience."