Rui Shirasagijō, known internationally as Lui Shirosagi, is a supremely skilled Blader boasting a significant competitive record, marked by five consecutive National Championships victories earned against formidable opponents like Valt Aoi and Shu Kurenai. Initially part of the Rideout team and the Supreme Four, he later ranked second then fifth within the Big Five. A transfer student sharing a class with Gabe Brunai, Rui typically kept to himself but developed an interest in Beyblade by observing Gabe's training, eventually joining the Bey Club. This sparked his renowned dedication and rigorous practice, such as training in isolated, icy regions to hone his skills. Rui possesses pale skin, light-blue and white hair, violet eyes with distinctive rings, and sharp teeth. During *Beyblade Burst Turbo*, he grew noticeably taller and adopted new attire: a sky-blue shirt with violet diamond markings and borders, dark-blue pants, a black elastic band worn across his waist and shoulder, white boots featuring violet accents and black diamond patterns, and a long white winter coat replacing his feather boa. His hair lengthened further later; when resonating with his Beyblade, it ignites and moves in a fire-like manner. Personality-wise, Rui exhibits aggression and intensity, displaying ruthless battle tactics. He inflicted significant injuries, notably carving a scar on Shu Kurenai's face and damaging his recovering shoulder, fostering deep animosity. He selectively battles opponents he deems worthy and openly criticizes those falling short of his standards, dismissing Valt as a "terrible Blader" for Valtyek's perceived untapped potential. Rui disdained crowd encouragement and initially rejected sportsmanship, criticizing admiration of opponents. However, he holds a sense of honor, refusing to battle injured opponents despite his earlier actions against Shu. Rui's demeanor evolved across the series. In *Turbo*, he softened slightly, showing interest in Aiger Akabane due to Valt-like similarities and becoming less overtly rude. This continued in *Surge*, where interactions with Dante Koryu fostered greater kindness, friendliness, and heroic traits, such as preventing Hyuga Hizashi from falling off a mountain. His competitive drive endured, but he showed respect, acknowledging Aiger's Luinor Cup victory and gifting him a Level Chip. Rui's Beyblade journey advanced each season. In *Turbo*, wielding Brutal Lúinor 13 Jolt, he challenged Valt Aoi for the World Championship title; their match ended in a tie after mutual Burst Finishes destroyed the stadium. He later dominated multiple opponents simultaneously, including Aiger, Ranjiro, and Fubuki, with Burst Finishes, establishing the Luinor Cup tournament. Initially viewing participants as "amusement," he ultimately respected Aiger after losing to him in the Cup finals. His Beyblades progressed from Lost Luinor Nine Spiral (*Burst*) to Nightmare Luinor Destroy (*Evolution*), then Brutal Luinor 13 Jolt (*Turbo*), and later Rage Luinor Destroy' 3A (*Surge*). Special moves like Brutal Squall use aerial maneuvers to amplify attack power. Pivotal battles shaped his trajectory. Before the series, his National Championship victory over Shu resulted in Shu's facial injury. During the Individual Tournament finals against Valt, he rejected a win from Valtyek's self-bursting, demanding a rematch to validate his skill. Losses to Free De La Hoya and Shu Kurenai in *Evolution*—where Nightmare Luinor was destroyed—catalyzed a shift in perspective, leading him to laugh joyfully and embrace new challenges. This growth manifested in *Turbo* as he engaged emerging Bladers like Aiger, signaling a departure from earlier isolationism.