Atsuhiro Sako, alias Mr. Compress, operates as a villain within the League of Villains and its successor, the Paranormal Liberation Front. Descended from Oji Harima, a legendary thief renowned for stealing from heroes to aid the common people, he embraces this lineage, framing his actions as a modern rebellion against systemic corruption. Standing 181 cm tall with pale skin, curly brown hair, and a pointed nose, his striking appearance features a signature masked ensemble: a balaclava, top hat, and interchangeable geometric-patterned masks. Following the loss of his left arm during a clash with Overhaul, he employs a mechanical prosthetic—later damaged and replaced amid battles with the Meta Liberation Army. Atsuhiro blends theatricality with calculated pragmatism, reveling in dramatic spectacle through monologues and performative combat, though his showmanship sometimes risks tactical errors. Despite this flair, he acts as a stabilizing mentor within the League, prioritizing unity and swiftly avenging allies, as seen in his retaliation against Overhaul after Magne’s death. His Quirk, Compress, enables him to condense objects or living beings into marble-sized spheres via touch, preserving their properties while reducing weight for transport. Skilled in partial compression, he can target specific body parts to disable foes, exemplified by severing Overhaul’s arm. Post-injury, restricted to his right hand, he adapts with decoy marbles and projectile attacks using decompressed debris. Pivotal moments underscore his strategic impact. During the Forest Training Camp invasion, he secures the capture of Katsuki Bakugo and Fumikage Tokoyami through stealth, evading pursuers with acrobatic precision. In the Shie Hassaikai conflict, temporary Quirk suppression leads to his arm’s destruction by Overhaul, though he later retaliates by maiming the yakuza leader. The Paranormal Liberation War sees him sacrifice body parts to free comrades, culminating in a climactic "final performance" where he unveils his heritage and engineers their escape before capture. Post-war, detained alongside Spinner, he endures as one of the League’s few survivors. His legacy intertwines with Harima’s ethos, positioning his crimes as an evolution of Harima’s rebellion against inequality, pursued through unapologetically criminal means.