Mitsunari Tokugawa serves as the organizer and proprietor of the Tokyo Dome Underground Arena, a venue hosting no-rules combat among diverse martial artists. Elderly at approximately 80 years old, he stands 147 cm (4'10") tall with a bald head, grey bulging eyes, and exclusively wears traditional kimonos varying in color across adaptations. Though non-combatant, he possesses encyclopedic knowledge of global martial arts from decades of observing matches. His personality balances an obsessive fascination with combat against moral boundaries. He prioritizes spectacle over safety, threatening medical staff to allow lethal duels like Baki versus Jack Hanma, and manipulates events—such as abducting the prehistoric Pickle to force a fight with Musashi Miyamoto—disregarding broader consequences. Yet he opposes cannibalism, intervening to stop Pickle from consuming defeated fighters, and displays empathy: grieving Doppo Orochi’s near-fatal injury and blaming himself for Retsu Kaiou’s death after lifting the arena’s weapons ban. Tokugawa demonstrates keen strategic intelligence, notably outmaneuvering Yuujirou Hanma ("Earth’s strongest creature") by using concealed snipers to tranquilize him with sedatives sufficient for a blue whale. As the 13th head of the Tokugawa clan claiming descent from Tokugawa Mitsukuni, he wields significant influence under the honorary title "Gorōkō" (Noble Elder). He leverages his sociability to maintain powerful connections, including friendships with Japanese prime ministers Yukio Hatoyama and Naoto Kanzaki, US General Gerry Strydum, and fighters like Doppo Orochi, alongside a complex acquaintance with Yuujirou. He hosts tea parties discussing combat philosophy and match outcomes. Tokugawa’s history with fighters began when 13-year-old Baki Hanma defeated his bodyguards, including Shuumei Kanou, to demand arena access. Impressed, Tokugawa admitted him and later facilitated Baki’s early matches against Koushou Shinogi and Mount Toba. He witnessed Yuujirou’s first arena appearance, arranging Yuujirou’s fight against Doppo, and orchestrated the global Maximum Tournament in his arena—recruiting fighters worldwide and offering a Pankration belt. The tournament concluded with Baki defeating Jack Hanma. Beyond matchmaking, Tokugawa sanctioned increasingly perilous encounters with non-human combatants like Pickle and the resurrected Musashi. These decisions, driven by his quest to witness ultimate strength, often led to catastrophic outcomes, cementing his morally ambiguous authority within the fighting world.