Koko serves as a main character in the horror anime series *Nanashi Kaidan*. He appears as a young boy with short blonde hair cut to his ears and striking blue eyes. His signature look includes a hoodie and a distinctive hairpin.

Quiet and withdrawn, Koko keeps largely to himself, avoiding interaction with nearly everyone around him. His social circle consists almost exclusively of Bon, a girl descended from a lineage dedicated to sealing supernatural entities. This single connection highlights his isolated existence.

Koko inhabits a world shaped by childhood fears, populated by unseen presences and disturbing phenomena central to the series' horror stories.