Marcus doesn’t remember his biological father and was raised by loving adoptive parents, who also happen to be freelance henchmen for supervillains. He considers his adopted parents his true family and has no regard for the Monkey King.
When Marcus was a child the family lived in Gotham City, until one night Batman broke into their home during a thunderstorm and attacked his parents, looking for information on their current employer. When he realized there was a child in the house Batman left, but Marcus was traumatized and suffered panic attacks for years afterwards. He was left with an abiding hatred for superheroes and phobias of bats, thunderstorms and water. The family left Gotham and began travelling around the country as his parents sought employment with villains around the country. The frequent moves made if difficult for Marcus to make friends, as did his mental health issues
The family returned to Gotham for Marcus’ sophomore year as his parents took a job with The Penguin. Marcus attended Gotham City High School where he quickly ran afoul of a trio of bullies, who saw him as an easy target due to his fears. The school janitor Mr. Zhu encouraged him to face his fears by leaping into the school swimming pool, and after a particularly bad incident where the bullies beat him up and stole his prized sneakers, he jumped in. He was transported to the Monkey King’s home on Flower Fruit Mountain, where Mr. Zhu revealed his true identity as the Monkey King’s old comrade Shifu Pigsy. He placed a circlet on Marcus’ head and unlocked his powers, telling him a great evil was coming and his training had begun.
Marcus returned to Earth in monkey form and attacked the bullies who picked on him. Damian Wayne saw him and called his father to tell him there was a metahuman loose in the school. They tried to stop him as Batman and Robin, which resulted in Marcus getting his head cut off with a batarang. Marcus survived thanks to his powers, but in his fear he began to revert to human form, and would have died if Pigsy hadn’t saved him and reattached his head at the last moment.
Marcus told Pigsy he wanted nothing to do with him and even removed the circlet, but the next morning he woke up to find it back on his body. At school, Pigsy told him that the circlet could not be removed and taught him how to transform at will. Pigsy made the circlet constrict around Macus’s head and began his training, telling him that he would loosen the circlet if Marcus could snatch an envelope from his hand.
The Shugel-Shens later relocated to Philadelphia, where Marcus would attend Fawcett High School and befriend Billy Batson.