Haruo Koga is a 17-year-old Japanese boy with tousled medium-length black hair, rectangular glasses, and a relaxed wardrobe favoring slate blue long-sleeved shirts paired with khaki pants. A former track and field standout, he balances athletic discipline with a creative drive for music composition. His past includes residing near the Mutoh family before disaster reshaped their lives.

When a catastrophic earthquake strikes, he retreats to a secluded shrine, drowning his grief in music through noise-canceling headphones—a coping mechanism for emotional turmoil. Forced into action as chaos escalates, he integrates into a survivor group, leveraging his agility and strategic thinking. His athleticism proves vital when he races against collapsing infrastructure to secure a crucial memory card lodged on a precarious platform. Though he successfully tosses the card to an ally, a sudden tidal surge overtakes him mid-retreat, claiming his life.

Beneath his resilience lies unresolved grief over his mother’s death and his abrupt exit from competitive sports, fueling introspective silences and raw vulnerability. A quiet meal of curry in Shen City underscores his internal battles and hesitant steps toward acceptance. His arc evolves from isolated mourner to decisive leader, prioritizing collective survival over self-preservation.

Interactions with peers reveal layered contradictions: gentle empathy clashes with rash decisions under pressure, while his history as both athlete and artist informs his problem-solving. This duality shapes his journey—a youth reconciling loss, responsibility, and fleeting moments of connection amid ruin.