Jeffy

Jeffy François Jeffy is the tritagonist of the SuperMarioLogan franchise. He is Mario's younger adopted son and sometimes an antagonist.

He made his debut on January 24, 2016, Mario The Babysitter! as the main antagonist. Ever since that day, Jeffy has been very popular, similar to Bowser Junior. Despite this popularity, Jeffy has also caused much controversy and is generally hated among older SML fans. He is the main antagonist in his debut Mario The Babysitter, Jeffy's Homework, Jeffy Gets Potty Trained, Jeffy's Bedtime, Jeffy's Bad Word, Locked Out, Jeffy's Tantrum, Jeffy's Cat Piano Problem, and Jeffy Plays Fortnite.

Despite being an antagonist, he is the main protagonist of some SML episodes such as Detective Jeffy!, Jeffy's Parents!, Jeffy Gets Bullied!, and Jeffy's Bad Christmas!.

He is the oldest son of Nancy and Jacques Pierre François, but since Jacques Pierre François died and Nancy went to jail in Jeffy's Parents!, he is now currently the adoptive son of Mario and his wife, Rosalina.