OVA
Description
Kazuma Hoshino is the main protagonist of the original visual novel, anime series, and related media. He relocates from an unspecified city to the rural town of Yamabiko primarily to benefit his younger brother Ayumu Hoshino's delicate health, specifically asthma. This move represents a significant life change and initially brings social difficulties.

Physically, Kazuma is an average-height teenage boy with brown hair, often styled with spiky bangs. He has blue eyes, though they are depicted as brown in the visual novel. He is frequently seen wearing his Yamabiko South Academy uniform: a white shirt, brown tie, and black trousers. In non-school settings, he wears casual attire like t-shirts and jeans. His athletic background includes prior tennis club membership, contributing to proficiency in sports like swimming.

Kazuma's personality centers on warmth, kindness, and a proactive, gentlemanly demeanor. He exhibits a strong protective instinct, particularly toward Ayumu, reflecting a notable brother complex. Despite early ridicule and distrust stemming from an accidental kiss with Ui Nakatsugawa during their first encounter—which led to rumors labeling him a "playboy"—he gradually earns respect and affection through consistent kindness and genuine intentions. While generally polite, he occasionally displays perverted thoughts during internal monologues or gameplay scenarios in the visual novel, though these are not dominant traits.

A subtle, recurring element involves fragmented childhood memories of Yamabiko, suggesting he lived there before but recalls it only through occasional flashbacks. His development across the series shows maturation from initial social missteps to forming meaningful bonds. Key relationships include his familial devotion to Ayumu, an evolving romance with Ui Nakatsugawa culminating in a mutual confession and relationship, friendship with the eccentric classmate Daigo Minamikokubaru—who respects him as "bro"—and a guardian-like dynamic with Senka Yorozu, the landlady of Yorozuyo Inn where he and Ayumu reside.

In the OVA, his protective nature intensifies briefly, displaying uncharacteristic aggression toward Daigo after a compromising situation involving Ayumu in a swimsuit, highlighting his underlying brother complex. His narrative arc emphasizes adaptation, reconciliation with his past, and the steady building of trust within his new community.