Taiju Oki is a tall, muscular man with spiky brown hair and distinctive vertical stone markings under his eyes; these markings were later replaced by identical paint following his second depetrification. He typically wears a sleeveless cloak tied with a rope and primitive boots, though he occasionally adopts roles like "Dr. Taiju" by donning a lab coat over modern clothing. Born in modern Japan, Taiju lost his parents young. He formed a close childhood friendship with Senku Ishigami and Yuzuriha Ogawa, participating in experiments such as crafting a swimming suit for Senku's astronaut father and launching handmade stuffed toys into near orbit. By high school, Taiju was known for his pacifism, having never struck another person, and held unconfessed romantic feelings for Yuzuriha for five years. On the day he resolved to confess to her, a global petrification event turned humanity to stone for roughly 3,700 years. Taiju remained consciously aware throughout this period, sustained solely by his determination to reunite with Yuzuriha and Senku. Revived on October 5, 5738, Taiju joined Senku in developing a revival fluid using nitric acid and fermented grape wine. His suggestion to use grapes for winemaking proved crucial to the formula's success. After reviving Yuzuriha, Taiju shielded her from Tsukasa Shishio's aggression, enduring a debilitating kick without retaliation due to his pacifist principles. He and Yuzuriha then infiltrated the Tsukasa Empire as spies to gather intelligence while secretly repairing petrified statues. Following the merger of the Tsukasa Empire with the Kingdom of Science, Taiju was appointed leader of the Farming Division within the Power Team. His responsibilities expanded during voyages to Treasure Island and America, where his exceptional stamina allowed him to transport multiple petrified statues underwater without supplemental oxygen. He remained conscious during a later seven-year global petrification event and contributed to the moon-landing project. He ultimately married Yuzuriha. Taiju's personality blends exuberant enthusiasm with steadfast loyalty. He approaches tasks with unwavering diligence, often vocalizing his efforts loudly. Despite his emotional nature, he maintains self-control and prioritizes non-violent solutions, refusing to harm others even under attack. His deep admiration for Senku drives him to support scientific endeavors, though his limited scientific understanding restricts him primarily to physical labor. While often perceived as unintelligent—evidenced by ideas like finding calcium carbonate in long-destroyed gym storerooms—he occasionally demonstrates practical ingenuity, such as applying seashells as soil fertilizer or recalling subtle behavioral cues like Senku's neck-cracking habit as a coded signal. His mental resilience is further evidenced by maintaining consciousness during repeated petrification events. Taiju possesses immense physical strength, enabling him to hurl boulders, restrain powerful opponents like Oarashi, and carry heavy loads over long distances. His durability allows him to withstand attacks that would incapacitate others, including Tsukasa's strikes. His most notable trait is near-limitless stamina, permitting feats like running 80 kilometers in five hours or performing consecutive deep-sea dives. He speaks basic English with limited fluency. His primary weakness lies in below-average logical reasoning and scientific knowledge, often leading to misunderstandings of fundamental concepts. However, he compensates through sheer determination and a willingness to learn practical applications, such as farming techniques taught by Senku.