Kaku Kaioh, formerly known simply as Kaku, stands as the Supreme Grandmaster of Chinese Kenpo and the Kaioh of Kaiohs, the undisputed highest authority among martial artists bearing that title. He has reigned as champion of the Raitai Tournament for an entire century. In his youth, Kaku possessed a massive, muscular physique built through bodybuilding. He dismissed martial arts philosophy, believing solely in raw physical strength and the inherent dominance of the strong over the weak. This belief shattered when an elderly Chinese master effortlessly defeated him. The humiliating loss drove Kaku to abandon bodybuilding completely and dedicate himself to mastering Chinese Kenpo. Embracing a training philosophy centered on embodying "weakness," his formidable muscles atrophied over decades. By the time of his primary appearances, he presents as an extremely frail old man, standing 155 cm (5'1") tall and weighing roughly 40 kg (88 lbs). He possesses a skeletal frame, long white hair, deeply wrinkled skin, and gnarled fingernails. He typically wears a Chinese cap, round glasses, a light-colored tangzhuang jacket and pants, and kung fu shoes, often using a wheelchair outside of combat. Even simple tasks like using chopsticks require effort due to his frailty. Yet, his martial arts mastery remains unparalleled. He is approximately 146 years old and is the father of Shunsei Kaku. Over a century of training and study has granted Kaku profound knowledge. His perception is exceptional, allowing him to instantly discern an opponent's mentality, fighting style, power level, and martial arts lineage merely by observation. He exhibits ruthless pragmatism and deep pride in Chinese martial arts and culture, demonstrated by actions like stabbing association elders or severing limbs to enforce discipline. Emotionally reserved, he has forsaken life's pleasures in his singular pursuit of strength and supremacy, though he acknowledges Yuujiro Hanma's power. Highly intelligent and deceptive, Kaku employs cunning tactics to survive battles he cannot win outright. His signature technique is Xiaoli (Shaori), perfected beyond any other practitioner. Xiaoli grants two key abilities: Defensive Xiaoli, absorbing and nullifying damage through supreme body control and relaxation, and Offensive Xiaoli, which absorbs an opponent's kinetic energy, combines it with his own, and reflects it as "the ultimate strike." This technique grants him hyposthenia, enabling extreme force manipulation. Despite his fragile body, Offensive Xiaoli grants him striking strength and durability capable of town-level destruction or higher. His body control extends to feigning perfect clinical death by stopping his heart and restarting it later, a survival tactic used against Yuujiro Hanma, supported by biological manipulation. Kaku demonstrates supersonic attack speed, capable of cleanly slicing objects like eggs with his hands. He utilizes the Hitless Blow technique for amplified strikes. A master of various weapons, particularly swords (likely matching Retsu Kaioh's skill), he also possesses stealth mastery, enabling him to approach formidable fighters undetected. His fighting style emphasizes precision and efficiency over brute force. During the Great Chinese Challenge Saga, Kaku captains the Chinese team in the Raitai Tournament. He swiftly defeats Kaiou Samwan with a tactical groin strike. Disappointed with other Kaious, he forms an alliance against the American-Japanese fighters. In the tournament's final match, he faces Yuujiro Hanma. Utilizing Xiaoli, Kaku absorbs and redirects Yuujiro's power, momentarily overwhelming him and forcing Yuujiro to activate his Demon Back. However, Yuujiro's "Ultreme Violence" penetrates Kaku's defense. To survive, Kaku employs his fake death technique, stopping his heart. After reviving, he acknowledges Yuujiro's strength, bestowing the title "Hanma Kaiou," and suggests a rematch in a hundred years. Kaku later reappears to assist Kaiou Retsu in training Katsumi Orochi, aiding in the fusion of Chinese Kung Fu with Karate. During this period, he exhibits a more amiable and comedic personality compared to his earlier ruthlessness. His techniques, especially Xiaoli, remain frequently referenced when analyzing similar abilities like Shibukawa's Aiki, underscoring his enduring influence as the supreme authority in Chinese martial arts.