At an unknown point in time, presumably during the Apocalypse World version of the Apocalypse, Michael took this man as his vessel. With this vessel, Michael fought against his brother Lucifer and was finally able to kill him.
Michael continued to use this man as a vessel as he enslaved his world and caused a never-ending war between angels, humans and demons.
In 2018, during a fight in the Men of Letters bunker in the Main Universe, Michael was severely injured by the Nephilim Jack to the point that his vessel's eyes began to bleed. In the aftermath, Michael told Dean and Castiel that he was too weak to fight the super-charged Lucifer, particularly in "this banged-up meatsuit." Instead, Dean offered a deal where he would become Michael's vessel in exchange for Michael powering Dean to fight Lucifer while Dean remained in control. Dean told Michael that as his true vessel and the Michael Sword, Michael would be more powerful than ever using Dean as a vessel instead of this man. After Michael accepted the deal, Dean said "yes" and Michael took Dean as his vessel instead.
After Michael's departure, his vessel presumably died, either of the strain of being the vessel of an archangel for so long or from the severe injuries inflicted by Jack. After leaving Dean, Michael takes on a female vessel instead of this man again, further suggesting that he is dead.
- Season 13