Kazumi Yoshinaga serves as the older brother in the Yoshinaga family. His younger sister Futaba acquired the sentient gargoyle statue Gar-kun through a lottery win, introducing the statue into their home. Kazumi frequently acts to prevent Futaba from instigating trouble stemming from Gar-kun's presence and actions.

He bears a strikingly feminine appearance, often leading strangers to mistake him for a girl, which causes him discomfort during social encounters. His personality contrasts with Futaba's aggressive nature, as he embodies a gentle demeanor and actively mediates family conflicts.

Kazumi shares a strong physical resemblance with his mother, who also employs wrestling skills for family discipline. He prefers peaceful resolutions and avoids confrontation whenever possible.