Nishio

Nishio is part of Eisuke Yamauchi's crew in Five. He's one of his most trusted subordinates, and part of the enforcer group under his command.

He abducts Kazuo on his own volition in order to help Eisuke, who's being strongly pressured on the Phantom Thief case.

Deck
Nishio runs a Mister Deck, spearheaded by the triplets demigods "The Hot Mister", "The Cool Mister" and "The Mild Mister" (placeholder names subject to change). These triplets are similar to "Exodia" in the way that the player needs to gather all three cards in order to Summon these powerful monsters, and needs to build an entire strategy focused on them (based on gathering trios of cards with the same name), but the payoff is incredible.

Because of this hard strategy, Nishio comes out as an average player in early game, but becomes a fearsome foe when he brings out the triplets demigods. Faced with these powerful monsters and an extremely tense situation involving his and his friend's safety, Kazuo is forced to use his Code Card for the first time against him.