Master Mario was an ex-WOOHP employee who developed many of WOOHP's fighting techniques. However, his WOOHP employment was terminated after he proposed creating a commercialized version of the fighting routines for sale to the public. Wanting revenge for his dismissal, Mario brainwashed people to create an assault force that would destroy WOOHP headquarters.
His only appearance was in the episode "WOOHPersize Me!". He was defeated by Clover, Samantha, Alexandra, and Britney. After being arrested, he was presumably taken into custody and jailed or had his memory of working with WOOHP permanently erased for good.
He is extremely muscular and very self-absorbed, as he's shown to have many framed pictures of himself in his lair, posing and/or flexing his muscles.
- He is named after Nintendo's mascot, Mario.
- After seeing all the pictures of his that he had up on the walls, Alexandra said that he must have more pictures of himself than even Mandy.