Nagomu Irino, a tall young adult with dark blue-gray hair and customary white confectionery chef attire, stands between 180-240 cm—a height inferred from comparisons to standard Japanese doorframes. Born into Kyoto’s historic Ryokushou sweets shop family, he abandoned his heritage after high school to pursue an unsuccessful music career in Tokyo. A decade later, his father’s hospitalization draws him home, where he discovers the family has appointed 10-year-old Itsuka Yukihira, a girl abandoned at Ryokushou by her father, as heir instead.

Gentle and altruistic, Nagomu harbors a profound love for wagashi and prioritizes others’ well-being, initially serving as an emotional anchor for Itsuka despite his own insecurities in confectionery craft. His evolving role shifts from brotherly companionship to a steadier, parental guidance, fostering her trust. He mediates conflicts with quiet empathy, exemplified by discreetly helping a crossdressing colleague regain self-assurance.

Though his departure strained relations, particularly with his disapproving father, Nagomu’s return sparks gradual reconciliation. His mother tasks him with aiding Itsuka’s healing from abandonment, forging a bond rooted in mutual dedication to Ryokushou. He consciously avoids replacing her biological father, instead nurturing respect and shared purpose.

His name Nagomu (和) echoes themes of harmony, reflecting his role in mending emotional rifts, while Irino (納野)—"settlement" and "field"—symbolizes reintegration into familial and communal duties. Outwardly carefree and optimistic, he privately grapples with unresolved tensions: his failed music aspirations, complex history with an ex-girlfriend, and the quiet acceptance of a life diverging from initial dreams.