Mathmatica,「マティマティカ」(Mattimatika) is the 10th ranked Pro LeagueDuelist who wears a red suit covered in numbers. He challenges Damon to a Duel during the Genex Tournament but loses. Prior to this, he is shown defeating several Duel Academy students, resulting in others actually running away to avoid Dueling him. He manages to catch up to the others, but ends up losing to Damon.
In the dub, he rhymes what he says with math equations.