Blueno operates as a government agent undercover in Water 7, posing as an unassuming bartender while secretly pursuing CP9’s mission to locate the ancient weapon Pluton’s blueprints—a five-year endeavor marked by feigned alliances with figures like Franky. Unlike his eccentric CP9 counterparts, his serene composure mirrors the World Government’s calculated tactics, evident when leveraging Nico Robin’s traumatic past to ensure compliance. His analytical precision surfaces during the Enies Lobby crisis, detecting anomalies like Spandam’s disconnected Den Den Mushi, which drives him to independently confront Luffy.

Ranked fourth in CP9 with a Doriki level of 820, Blueno masters Rokushiki martial arts, particularly Tekkai techniques such as Rin and Gou—the latter briefly enduring Luffy’s Gear 2 assaults. The Doa Doa no Mi Devil Fruit enables door creation on any surface, including air, facilitating stealthy infiltration, tactical traps, and escape into extradimensional spaces.

As Luffy’s first major Gear 2 adversary at Enies Lobby, Blueno’s strategic adaptability emerges in their clash, though he falls to the pirate’s heightened speed. Surviving the Buster Call’s devastation via an Air Door sanctuary, he shields CP9 allies and facilitates their retreat into exile. Post-timeskip, he resurfaces promoted to CP0, reflecting steadfast loyalty to the World Government’s agenda.

In *One Piece: Episode of Merry*, his role condenses yet retains core Enies Lobby elements, including pivotal confrontations and contributions to Robin’s manipulation.

Raised in the North Blue and drilled from childhood alongside CP9 elites like Rob Lucci, Blueno’s indoctrination into ruthless service eclipses personal bonds—a mindset延续ing into his CP0 tenure, where he perpetuates the organization’s pragmatic efficiency.