Sadayoshi Karimata stands as the narrative's primary antagonist, a Sengoku-period warlord who orchestrated the Ayawatari clan's destruction to seize their advanced Karakuri doll technology. Acquiring these secrets fueled his rapid military expansion. He forged an army of murderous puppets, the "Deathless Ninjas," designed to relentlessly haunt and eliminate his enemies. Karimata further augmented his own power by fusing with Hisashige Ayawatari's unfinished masterpiece, the "Living Doll," gaining superhuman strength.

His oppressive rule maintained control through systematic child abduction. These children were flayed alive, their harvested skin serving as the essential material for constructing his puppet soldiers. This horrific process transformed his castle into an environment described as "hell on earth." The creation of the puppets relied entirely on the skin of living children, a brutality exemplified by Rangiku Fumiwatari, who bears a massive scar from shoulders to back. This injury was inflicted by her own father under Karimata's influence or direct orders.