The king of underground fights, in which players do not always abide by the rules and cheating is allowed. He is a strong cardfighter who, despite having underlings to do his bidding, does not trust anyone except himself and his cards. He is also proficient with a whip. However, after being defeated by Kai, Jun develops somewhat of a friendly relationship with him. In season 2, Jun reappears at the Japan Stage of the VF Circuit. He dons the disguise of King Z and is a part of Team Unknown along with Yuri (as Queen Y) and Tetsu (as Joker X). He later unveils himself to Aichi when he faces off against him near the end of the Japan Stage. Jun first uses a Dark Irregulars deck and later a Dimension Police deck.