Grandpa, Michiko Yamakawa’s grandfather, plays a minor yet pivotal role in the first episode of *Strike Witches*. During an afternoon wagon ride through Fuso, he offers Yoshika Miyafuji a lift. A sudden encounter with a stray dog spooks the horse, overturning the wagon and injuring Michiko. The accident compels Yoshika to instinctively channel her dormant magical abilities to heal the wound—an act witnessed by Mio Sakamoto. This moment of unintended revelation draws Mio’s scrutiny and catalyzes the series’ events. His involvement is limited to this incident, with no expanded backstory or later appearances in related media.