Yui Uehara grew up in a village in Nagano Prefecture with Kansuke Yamato and local police officer Kuroto Kai. Inspired by Kai, she joined the police force in her early twenties. After Kai's mysterious death, she and Yamato dedicated themselves to solving his case. When Yamato suffered critical injuries and was presumed dead during an unrelated investigation, Uehara resigned from the police. She strategically married Yoshiro Torada—changing her surname to Torada—to infiltrate a family she suspected in Kai's death; her husband genuinely cared for her despite the marriage's non-romantic nature. Approximately a year later, her husband became the first victim in a series of murders that ultimately led to Kai's case being resolved with Conan Edogawa and Heiji Hattori's help. Following these events, Uehara rejoined the police force, reverted to her maiden name, and now serves as Yamato's assistant police inspector at Nagano Prefectural Police headquarters. Uehara is friendly and considerate, providing a contrast to Yamato's stern demeanor; their differing personalities complement each other professionally. Her behavior frequently implies romantic feelings toward Yamato, though their working relationship has prevented significant personal developments, though Yamato appears receptive. She once metaphorically described her feelings for him using the "wind, forest, fire, mountain" concept: he appears like the wind, departs quietly like the forest, ignites her passion like fire, yet remains unmoving like a mountain. She regrets not confessing earlier, believing this hesitation contributed to Yamato's accident and her marriage into the Torada family. In investigations, Uehara demonstrates perceptive and deductive abilities. During the Furinkazan case, she identified the culprit's next target and intervened, though overpowered until Yamato, Conan, and Heiji arrived. She later privately informed Conan that Yamato sought Kogoro Mouri's assistance primarily to involve Conan, recognizing his deductive skills. In the Red Wall case, she saved Taka'aki Morofushi's life after an attack, acting on Yamato's orders to monitor him. She also collaborated with Yamato in an undercover operation posing as a couple to apprehend a suspect. Accompanying Yamato to investigate an assault at the Nobeyama radio observatory during the Mount Mitakara avalanche incident, Uehara drove him after his blinded left eye experienced sudden pain triggered by the facility's parabolic antenna. Later, en route to a shooting incident site, they were ambushed. Taking shelter in a mountain hut with Morofushi and others, Uehara assisted in protecting the group during subsequent attacks. When an avalanche was deliberately triggered to bury them, she believed Yamato had died (later revealed as a ruse). Her reaction indicated deep personal concern extending beyond their professional relationship.