Kenji Koiso

Kenji Koiso (小磯 健二 Koiso Kenji) is the main protagonist of Summer Wars. He is a math-savvy 2nd year high school student (11th grade) and a moderator of the interactive computer world OZ along with Takashi Sakuma (Kenji's close friend). Kenji is less skilled in dealing with people. Kenji is invited by Natsuki Shinohara (Kenji's friend and the girl of his dreams) for Sakae Jinnouchi's 90th birthday with him being her fake fiance for the family reunion. After receiving a cryptic code on his cell phone and cracking it, he becomes a primary suspect for hacking into OZ.