Yō Uei began his career as a rule-breaking police officer in the pre-petrification era, infamous for excessive force against suspects. His petrification occurred mid-urination against a wall, highlighting his unprofessionalism. Revived by Tsukasa Shishio, he became a Tsukasa Empire enforcer. During the Stone Wars, he guarded Chrome but underestimated the captive’s intelligence, enabling an escape. Fearing retribution, he staged his death, abandoned the Empire, and directed subordinates to blame him entirely. He stands 177 cm tall with a lean, muscular frame. A persistent stone fragment perpetually covers his right eye, mysteriously reappearing if removed. His signature attire included a sleeveless grey yukata, spiked necklace, and ankle bracelets, later replaced by modern clothing and Kingdom of Science insignia after joining Senku. Initially abrasive and arrogant, he deemed pre-petrification humans superior and scorned revived individuals as "savages." He craved rank advancement and boasted of his strength, yet acted cowardly when confronted over failures. Despite flaws, he demonstrated sporadic loyalty—shielding subordinates from blame and expressing authentic awe at Senku’s inventions. His rivalry with Magma sparked comical clashes debating modern versus primitive human capabilities. Police training granted him tonfa expertise and moderate marksmanship. Post-revival rustiness initially impaired his shooting, but practice restored proficiency. Statistically, he rated: Power 3/5, Speed 4/5, Technique 5/5, Reach 1/5. As the Kingdom of Science’s primary firearm user during the Treasure Island Arc, he employed these skills. After fleeing the Empire, he encountered Homura and contemplated rescuing her to regain standing, only to find the Empire dissolved. Feigning amnesia, he joined Senku’s group under pretenses of redemption. As penance, he aided Yuzuriha in statue reconstruction and toiled in Taiju’s farming division. He reluctantly participated in sewing and balloon construction, often incentivized by power or money. In the Treasure Island Arc, Kirisame petrified him; after revival, he wielded firearms against Ibara’s forces. Missing pivotal shots initially, he eventually shot the petrification device from Ibara’s grasp. Repetrified mid-conflict, he revived later. During the New America City Arc, he nervously aimed at Tsukasa in a spar, gambled heavily aboard the Perseus, and engaged in combat against alligators and Stanley Snyder’s forces—his shots proving ineffective against an attacking plane. Skeptical about diamond creation in the South America Arc, he grew enthusiastic upon success. He fought for the petrification device, sustained a non-fatal gunshot wound, and petrified during the global event. Revived nine years later in Corn City, he assisted computer construction, complaining about labor until enticed by monetary rewards. He later delivered corn and the petrification device to Senku in Australia and aided rice harvesting in Indonesia. Post-story, he co-founded a law enforcement agency using his police background. His catchphrase "Weeeei!" and fondness for beer remained enduring traits.