He is just really rich (Powers:None)
Mitchell first appeared in Prisoner of Cell 25, when he, Jack, and Wade jump Michael at their school, Meridian High School, because they thought Michael ratted them out for stuffing him in his locker. The three had pulled tormented Michael before and did not want to be "told on" by him. They would have succeeded in pantsing and beating up Michael, the ultimate humuliation, but he shocked them with his powers, and out of fear they decided to quit picking on him.
He is next seen in Rise of the Elgen, when the Electroclan are in need of a place to stay and Jack proposes Mitchell's house. Mitchell is originally annoyed that Jack and Wade took Michael to California and not him, but changes his mind when he hears about the Elgen and the human boys' transformation into GPs.
It is revealed that Mitchell is very rich, with an enormous mansion as well as a pool house, where the Electroclan stay (Mitchell's parents are away on vacation. It is implied they are almost always away, leaving Mitchell alone, to do whatever he'd like, including aiding and abetting international fugitives). The Elgen stop by Mitchell's house looking for the Electroclan, but do not find them.
The Voice keeps a white van parked outside Mitchell's house to watch him, and supposedly protect him from the Elgen. It is unknown if this continued after the Electroclan left for Peru.
Mitchell did not appear in Battle of the Ampere, though he was mentioned, when Michael said that he'd much rather be back at Mitchell's house than in Peru
- Mitchell is extremely rich and lives in a mansion complete with multiple rooms and a pool house.
- Mitchell can play the viola, though he has not told Jack or Wade this (probably not part of the "tough guy" routine).