It's hard being an angel. Especially if you live in the shadows of Heaven's most controversial golden boy.
Michael has lived his childhood under the shadows of his one existing brother: the demon lord Lucifer. Although they are twins, Michael carries a great hate for his brother. Born under the prophesy that one of them would be the child of darkness, and the other the child of light, there was an immense pressure upon Michael, who was deemed inferior to his twin. Lucifer grew quickly and was soon a stunning young man, while Michael struggled to match his brother's power and natural leadership. Eventually the people declared Lucifel (as was his angelic name) to be the first morning angel - a great honour. Michael turned away from his brother and, wrought with childish jealousy, despised Lucifel, growing up thinking he was the child of darkness - a notion that the people around him, unfortunately, enforced by continuously looking down on his capabilities. When his brother turned against Heaven, it shattered Michael's foundation. He was assigned to drive his brother out of Heaven and into Hell, something he was pushed into emotionally unprepared. The incidents leading up to their final confrontation left an emotional scar on Michael which never healed.
Believing that his brother is finally sealed deep in Hell and unable to continue living, Michael spent his time getting into fights and hunting demons in the lower planes of heaven, until the waking of the Messiah upends his life all over again.