Voiced by: Ayaka Saito (Japanese), Jasmine Berg (English)

Koinosuke's only child, although having the appearance of a boy, Ayunosuke is actually a girl. Koinosuke entrusts her the Yagyu's successor task if he fails.

When Jiyu first blew the "Koinosuke Whistle", Ayunosuke appears in front of her eyes and gives her the Eyepatch, Jiyu quickly escapes and is chased by Ayunosuke. Since then, Ayunosuke has watched over Jiyu and often gets attacked by Freesia and questioned by Mikage. Eventually, she treats Jiyu's wounds and continues to convince her to wear the Eyepatch, but she refuses and says that she doesn't want to fight anymore; this makes Ayunosuke exhausted and transforms into a 300-year old body.

Later, she is revived after Jiyu wears the Eyepatch and witnesses her fight with Freesia. In the end, Ayunosuke is reunited with her father in the afterlife but she is seen at the last screen, sleeping in her father's doghouse.

Source: Wikipedia