Fourteen-year-old Kaoru is stranded with classmates on an uninhabited planet. He maintains a reserved and quiet demeanor, speaking minimally and keeping distance from the group, behavior rooted in survivor's guilt over the death of his friend Louis. Louis perished in space during an accident while the pair navigated an asteroid storm.

Characterized as a lone wolf, Kaoru frequently ventures off alone despite group concerns. He arrives with no possessions but exhibits strong resourcefulness and keen situational awareness, often spotting dangers or solutions before others. He demonstrates significant physical courage, repeatedly risking his life without hesitation to protect classmates.

During the survival ordeal, Kaoru gradually integrates more with the group while retaining his observant nature. He forms a particular connection with the group's leader, Luna, communicating most effectively with her. By episode 40, subtle narrative cues suggest developing romantic feelings toward Luna.

His reliability and survival skills make him a valued group member, contrasting his initial detachment. Kaoru also shows moral conviction, being among the first to confront Howard's entitled behavior when necessary.

His motivation stems from processing loss, mirroring Luna's experience of parental death. This shared trauma fosters an underlying understanding between them. His development occurs entirely within the group's survival journey, with no documented appearances in other media.