Monique "Mo" is Arthur's oldest cousin, whom Arthur remembers when she had been awful to him in the past reunions and tries to avoid her, until it is revealed that Mo isn't as bad as Arthur thought. She, like Arthur, plays the piano, and claims that Arthur is her favorite relative. So far, Monique is a one-off character who only appears in "Arthur's Cousin Catastrophe". She's 12 years old.