Senka Yorozu owns and operates the Yorozuyo Inn in Yamabiko, lodging Kazuma and Ayumu Hoshino following their move to the rural town. As a close friend of their father, she acts as their guardian. She stands 170 cm tall with a mature physique, blue eyes, and straight black hair reaching her hips, typically secured by a kanzashi ornament on her right side. Traditional yukata or kimono form her usual attire.

Her personality blends warm hospitality with firm discipline. She displays a motherly, frank demeanor and enjoys sake, yet enforces strict standards against rudeness. A mischievous streak emerges through teasing and flirtatious behavior. She resists being called "oba-san," insisting on "nee-san."

Raised in Yamabiko, she attended local schools and assisted her father at the inn before leaving for university. When her father fell terminally ill, she dropped out to return home, inheriting the inn burdened by guilt over missing his final years.

In the fandisc "Hoshizora e Kakaru Hashi AA," her dynamic with Kazuma evolves. After living together over a year, he develops romantic feelings during his part-time work at the inn and confesses. Senka initially rejects him, citing their ten-year age gap. Upon reflection, she accepts his second confession. Weeks later, she ends the relationship, fearing she might restrict his future opportunities like university or relationships with peers, and worrying he might regret staying. Kazuma, encouraged by friends, reaffirms his commitment, leading to their reconciliation.

Her connections include a familial bond with Kazuma and Ayumu, a professional rapport with Tsumugi Toudou—who addresses her as "okami"—and later, Tsumugi's employment at the inn post-graduation.