Kenji Koiso is the main protagonist of the anime movie 'Summer Wars.' A shy and intelligent high school student with a talent for mathematics, Kenji becomes embroiled in a crisis in the virtual world of OZ. After being invited by his classmate Natsuki to her family home, he finds himself at the center of a digital catastrophe threatening the real world. Kenji’s resourcefulness and courage are crucial in overcoming the challenges and saving both the virtual and real worlds.