Rei Furuya operates under the alias Tooru Amuro and the Black Organization codename Bourbon while working as an undercover investigator for Japan's National Police Agency Security Bureau. Childhood bullying over his mixed Japanese heritage led to frequent fights, with injuries treated by Elena Miyano at her clinic; her subsequent disappearance after joining the Karasuma Group deeply influenced his decision to enter the police academy. There, he excelled as top graduate alongside classmates and friends Hiromitsu Morofushi, Jinpei Matsuda, Kenji Hagiwara, and Wataru Date. Graduating into the National Police Agency, Furuya later infiltrated the Black Organization as Tooru Amuro. He meticulously isolated himself from past connections to protect his cover, posing as a freelance detective and part-time waiter at Café Poirot. This role evolved into an apprenticeship with Kogoro Mouri, maintaining proximity to the detective agency. Within the Black Organization, Bourbon specialized in intelligence and deduction. During this period, he encountered another undercover agent, Scotch, whose exposure led Furuya to a confrontation scene between Scotch and FBI infiltrator Shuichi Akai (alias Rye). Witnessing Scotch's suicide and misinterpreting Akai's involvement, Furuya developed lasting animosity towards him. Furuya's personality blends a cheerful, generous facade—marked by enthusiastic deductions, open emotional displays, and frequent food deliveries to the Mouri Detective Agency—with a darker, manipulative core. He employs psychological traps and ruthless methods, including plans to hospitalize innocents as bait or allowing evidence destruction to test others, alternating between protective instincts and disregard for safety when inconvenient. Gin notes his secretive, unpredictable nature, likening him to Vermouth. During the events of *The Bride of Halloween*, Furuya pursued a serial bomber responsible for Jinpei Matsuda's death three years prior. The bomber detonated a collar bomb, injuring his subordinate Yuya Kazami. A masked assailant then placed an identical collar bomb on Furuya, forcing him into hiding. Conan Edogawa assisted in disarming the device, during which Furuya recalled encountering the bomber "Plamya" during his academy years. The investigation uncovered links to the past bombing and a new threat targeting Shibuya's Halloween festivities. Furuya utilized a Heckler & Koch P7M8 pistol during these events. His abilities encompass exceptional deductive reasoning, information gathering, and observational skills noted by allies and adversaries alike. He demonstrates physical proficiency in boxing and jujitsu, alongside adept driving, lock picking, and guitar playing.