Suika is a teenage boy defined by his unyielding romantic pursuit of Suzu. He has confessed his love to her more than fifty times, yet every declaration meets rejection. This pattern establishes his core narrative purpose as a perpetually spurned suitor. He inhabits Suzu's same culturally complex society, blending diverse aspects of humanity, religion, and science, though his personal background—including family or origins—receives no elaboration. His interactions revolve solely around courting Suzu, with no evolution or resolution to his romantic efforts.

Suika remains detached from the central conflict concerning the Forbidden Grounds or the nature spirit Coluboccoro. His role is strictly confined to his unrequited affection for Suzu, functioning as a secondary interpersonal subplot separate from the story's primary ecological and destiny-driven themes. His portrayal across all documented media remains consistent, offering no further development or expanded backstory beyond this singular narrative arc.