Kofun-sama reigns as king of the Haniwa tribe. His tribe members provide unwavering service, cementing his leadership. The character's concept and his tribe's depiction draw direct inspiration from historical Japanese haniwa. These hollow clay figures, placed around burial mounds during the Kofun period (circa 300–710 AD), marked graves and served ritual purposes. Within the anime's narrative, his role centers exclusively on his kingship over the Haniwa tribe. Details regarding his specific background, character development, physical appearance, personality traits beyond his regal status, or appearances in other official media remain unexplored.