Kenji Koiso

The protagonist of this work is a 17-year-old high school sophomore attending Kuonji High School in Tokyo. He is a member of the physics club. He is shy and introverted by nature. He excels in mathematics, to the extent that he was considered a potential candidate for Japan's team in the International Mathematical Olympiad (though he narrowly missed the opportunity). His father is on a solo assignment overseas, and his mother is busy with work, so he mostly lives alone at home. He casually accepted a part-time job invitation from Natsuki and visited her family, the Jinnouchi household, only to be suddenly introduced as her fiancé and forced to play the role of a fake boyfriend. On the night of his visit, he responded to a code sent by Love Machine (though it was incorrect due to a typo on the last character), resulting in his account being hacked and falsely accused as the culprit of the chaos in OZ. He sets out to resolve the incident. Despite being at a disadvantage in the battle against the hacking AI "Love Machine," he motivates himself with the thought, "I haven't lost yet!" and his determination encourages the unity of the Jinnouchi family. Even after Natsuki's lie is revealed, Sakae pleads with him to "take care of Natsuki." The avatar he uses in OZ initially resembled a boy with round ears like Mickey Mouse, but after his account was stolen by Love Machine, it became a stylized squirrel (registered as a temporary avatar using the number Sakuma used when calling Kenji at the Jinnouchi household).