Onizaki serves as the primary antagonist, commanding a luxury yacht that functions as his operational base for non-consensual acts. His methodology centers on abducting individuals and administering a powerful aphrodisiac to force their participation in humiliating spectator events staged for his audience. He employs calculated psychological manipulation, specifically compelling each victim's partner to observe these acts to intensify degradation. His presence directly facilitates the central conflict involving Ai's captivity and exploitation, with his actions consistently embodying cruelty and exploitation.