Shuichi Akai, a British-American FBI agent of Japanese descent, was born in England to Mary Sera and Tsutomu Akai. The mysterious disappearance of his father during an inquiry into the murders of Kohji Haneda and Amanda Hughes catalyzed his path into law enforcement. He shares a guarded, secret-laden bond with his younger siblings, Shukichi Haneda and Masumi Sera, shaped by fractured trust and unspoken protectiveness. Relocating to the U.S. for education, he later joined the FBI to dismantle the Black Organization and uncover truths behind his father’s vanishing. Five years before the main timeline, Akai infiltrated the Black Organization as Dai Moroboshi, codenamed Rye. His mission entangled him romantically with Akemi Miyano, a low-tier member initially targeted to reach her sister Shiho Miyano—a key researcher. Though his intentions began as tactical, genuine affection bloomed. A fatal mistake by an FBI ally exposed his identity, culminating in Akemi’s execution by Gin. Her death forged his unrelenting vendetta against the organization, marked by his sardonic taunt of addressing Gin as "koibito" (lover). Post-infiltrator life, Akai emerged as the FBI’s strategic linchpin against the syndicate, dubbed "Silver Bullet" for his precision. To shield CIA spy Hidemi Hondou, he staged his death, adopting the alias Subaru Okiya—crafted with Yukiko Kudo’s aid—to covertly surveil Shiho (now Ai Haibara) and ally with Conan Edogawa. As Okiya, he balanced stealthy guardianship of Haibara with deliberate distance to avoid reigniting her trauma. Stoic and introverted, Akai cloaks emotions beneath tactical secrecy, often alienating allies like Jodie Starling through detached pragmatism. Yet loyalty surfaces in subtle acts: cryptic clues left for Jodie, clandestine martial arts training for Masumi. His tactical genius shines in operations such as outmaneuvering Black Organization snipers across 700 yards to disarm Gin. A master of Jeet Kune Do and ambidextrous sharpshooting, Akai’s expertise spans espionage, disguise, and strategic deception. His rivalry with Rei Furuya (Bourbon) simmers with unresolved tension over Scotch’s death, complicating their uneasy collaboration. During WSG-linked kidnappings, Akai traced threads to a 15-year-old Boston case, partnering with Conan to thwart an assassination via a custom silver bullet—echoing his moniker’s lethal symbolism. Relationships remain layered: mutual trust with Conan despite clashing methods, Ran Mouri’s recollection of his brusque yet protective New York intervention, and Haibara’s wary acknowledgment of his veiled guardianship. Akai’s narrative intertwines personal loss with relentless resolve, his layered motives and tactical brilliance anchoring him as both weapon and shadow in the war against the Black Organization.