It is implied that Michael is a doppelganger of the game's Mike Schmidt. Michael, along with the Ignited and Fallen animatronics are demonic doppelgangers according to the developer, Nikson, possibly brought to the real world by the curse of the haunted forest mentioned in the newspaper during the ending cutscene of the basement. He tried to be nice with Scott in the Attic opening cutscene, trying to have a talk with him before they arrive, but in the final cutscene, he takes a much more sinister tone, before killing Scott and taking over his body. This was only to hide his true nature, which is revealed when talking to Scott. He had a playful tone when talking to Nick, the youngest and the baby of the family. Michael had an insecure, but kind attitude with Scott's family, trying to help them to escape the animatronics.
Michael's appearance is described by Nick to 'not look like a dangerous person', but that's probably because he was really young when the incident happened. He also has golden glowing eyes, but this is possibly because of his possession abbility. He is described by Scott as 'looking like he just crawled out of a bonfire', meaning that he was severely burnt, which is confirmed at the end of the game.
Michael's appearance is never clearly shown in the game, and his figure can barely be seen at the end of the game.
