Brawl is a member of the Mayhem Squad.
He first appears with the rest of the Mayhem Squad in the story "Agenda". In the story he dislocates, the former Numbuh 1772, Mario's arm. While the rest of his team fights off Sector Q, Numbuh 3.14 continuously tries to order Brawl around, but to no avail.
Felix tried to order Brawl to attack Sector Q, but Brawl refused, stating he doesn't take orders from him.
Brawl's armor grants him super strength.