Tasuku Ryuenji, a seventh-grade student at Aibo Academy, serves as a prominent member of the Buddy Police, an organization dedicated to preventing misuse of interdimensional monster abilities. His surname, translating to "Dragon Flame Temple," reflects thematic connections to his capabilities. Partnered with Jackknife Dragon, he utilizes the Sky Circle buddy skill for flight and the Star Pulser core gadget. Their bond originated during "The Disaster," the catastrophic event that claimed Tasuku's family, leaving Jackknife as his sole remaining connection. This trauma shaped his conviction that adults excessively shelter children, driving his desire to prove independence through early law enforcement involvement. Initially wielding a Dragon World deck, Tasuku maintained an undefeated record until losing to Gao Mikado, forging a friendly rivalry. His sense of justice later corrupted by Kyoya Gaen, he joined the antagonistic Disaster group under the alias "Purgatory Knight." During this phase, he adopted a Darkness Dragon World deck featuring Purgatory Knights Leader Demios Sword Dragon as his buddy and utilized dark armor as his core gadget. This transformation stemmed from disillusionment with Buddy Police restrictions and trauma-induced conviction that children lacked power against adult-dominated systems. He embraced Kyoya's ideology blaming adults for global problems, displaying hostility and self-hatred over his family's fate. Following redemption, Tasuku underwent training in Dragon World, transitioning to a Star Dragon World deck with Star Guardian Jackknife Dragon as his buddy. Jackknife later evolved physically into Star Dragoner Jackknife. During the Triple D season, he temporarily left the Buddy Police to focus on studies but continued supporting allies. He acquired the Dragon Force of Joy ability, characterized by luminous energy and crystalline hair adornments, which evolved into the "Style of Justice" manifestation with enhanced power crystals and glow effects. In Future Card Buddyfight X: All-Star Fight, Tasuku participated in the Gao Genuine Gameface Tournament. He notably resumed his Purgatory Knight identity during a confrontation against the Supreme Dragon Deity of Creations, leading to a climactic "showdown of destiny" against Gao Mikado. His personality blends maturity with moments of inadvertent humor, such as misinterpreting nicknames. While generally maintaining composure, he exhibits fierce protectiveness and a willingness to defy orders for others' safety, alongside deep-seated guilt over his actions as Purgatory Knight. His relationship with Jackknife is familial, with both frequently risking themselves for the other. Stubbornness and an inflexible approach to justice represent recurring flaws, stemming from unresolved trauma. By Future Card Buddyfight Ace, Tasuku achieved the rank of Commissioner within the Buddy Police, indicating full reintegration into the organization and resolution of his earlier conflicts.