Arnold is the lost brother of Mario and Luigi. He wears orange, with green overalls. He first appeared in Mario Kart: Mushroom Tour as an unlockable character. 2 days later, he was in a game called The Lost Brother, where Mario and Luigi search for him. Finally, they find him in Twilight Town, being harassed by his rival, Warnold, and his Boos. They save him and bring him to Toad Town to live with them. He later gained his own apprentice, Suzette.