Yō Uei, a former police officer from the pre-petrification era, sports spiky auburn hair and a distinctive stone piece covering his right eye, which persistently returns despite repeated removals. He typically wears a grey sleeveless yukata, a large left shoulder pad, spiked necklace, and ankle bracelets, later switching to modern clothing after Yuzuriha opens a fashion store. Abrasive and arrogant, Yō frequently belittles others, dismissing post-petrification humans as "savages" and mocking their lack of scientific understanding, exemplified when he underestimated Chrome's escape attempt. Despite his modern background, he struggles with advanced concepts like Senku's GPS, questioning Senku's sanity. Cowardice defines him; he fled the Tsukasa Empire after Chrome's escape, faked amnesia to join the Kingdom of Science for safety, and avoids strenuous work like statue repair and farming. He can be motivated by promises of power or profit. His past includes rule-breaking, such as shooting suspects during arrests and urinating on a wall during petrification. Manipulative and power-hungry, he is susceptible to influence by Senku and Gen. Occasional redeeming qualities emerge. While fleeing Tsukasa's Empire, he instructed subordinates to blame him for Chrome's escape to protect them. He also committed to aiding Yuzuriha in reconstructing petrified statues as penance. After aligning with Senku, he evolves into a loyal Kingdom of Science member, expressing awe at Senku's inventions and wishing he had met him before petrification. Trained as a police officer, Yō wields tonfas with proficiency, capable of incapacitating opponents in single strikes. He demonstrates agility in pursuits, chasing Chrome and evading traps. Initially a poor marksman due to rustiness, he regains firearm skills through practice, wielding a gun during critical missions. His physical stats—power (3/5), speed (4/5), technique (5/5), reach (1/5)—highlight his close-quarters combat focus. Initially revived by Tsukasa, Yō served as an enforcer in the Tsukasa Empire. After Chrome's escape, he faked his death to avoid punishment and infiltrated the Kingdom of Science. He participated in projects like the hot air balloon and farming under Taiju, clashing with Magma over differing worldviews. During the Treasure Island Arc, he was petrified by Kirisame and later by Ibara after disarming him. Revived again, he fought in North America, getting shot during a mission to activate a petrification device. In the South America Arc, he assisted in diamond synthesis and battled American soldiers before being petrified in the global event. Nine years post-second petrification, Yō revived in Corn City. He expressed skepticism about crafting a computer but engaged in labor for money. He later transported corn and petrification devices across continents, harvested rice in Indonesia, and joined dam construction in Japan. His final petrification occurred alongside Gen during the Moon Mission Arc. Yō holds the record for most petrifications (five times), tying with Ryusui. His martial arts style derives from Okinawan traditions, and he exhibits a noted affection for Minami.