Kazuma Ikezawa

13 years old. A first-year middle school student and Natsuki's second cousin. In OZ, he is a world champion in a fighting game, with sponsors, and controls a tall rabbit-shaped avatar named "King Kazma." He calls his grandfather, Mansuke, who taught him Shaolin Kempo through OZ to overcome bullying, his "master." On the night Kenji arrives, he is seen alone in the storage room tinkering with his computer. Initially, he shows a cold reaction to Kenji, but after the incident occurs, he ends up cooperating with him. He later admires Kenji for solving the code and helps in resolving the incident.

In "Crisis of OZ," he is a first-year middle school student. He rises to become the world champion of OMC but questions why he continues to fight despite having no reason to. During Golden Week, he participates in the OMC tournament from his favorite internet cafe and meets Maki's avatar at the venue. Coincidentally, he ends up meeting her in real life as they are in adjacent rooms at the internet cafe. He is self-conscious about his height, which is not even 140 cm.

In "King Kazma vs Queen OZ," he is a sixth-grade elementary school student. He is a top-ranked player in OMC and is gradually overcoming the retaliation he faced in real life due to his winning streak in OZ last year. He enters the OMC summer tournament and passes the preliminaries. Due to the schemes of Kaho and Minami, he ends up going to the Jinnouchi household with them and their nemesis, Rikiya. Kaho has feelings for him, but he is unaware of it.