Atsuhiro Sako, alias Mr. Compress, operates as a theatrical villain within the League of Villains and later the Paranormal Liberation Front. Descended from Oji Harima, the legendary “Peerless Thief” who plundered corrupt heroes to aid the oppressed, Atsuhiro inherits a contempt for systemic heroics, channeling this disdain into his criminal pursuits. Adorned in a magician’s ensemble—top hat, masked balaclava, dark orange shirt, green-striped bolo tie, and knee-high boots—he embodies dramatic flair. Injuries mark his trajectory: a mechanical prosthetic replaces his left arm, severed by Overhaul’s Quirk-destroying bullet, while self-inflicted compression during the Paranormal Liberation War permanently damages his lower back. His Quirk, “Compress,” lets him shrink touched objects or beings into marbles for stealth captures, terrain alteration, or precise strikes. Tactical ingenuity manifests in decoy spheres, projectile attacks, and body-part compression to disable foes. Post-amputation, the ability activates solely through his right hand, constrained by its touch-based, arm’s-reach range. Notable actions include capturing Katsuki Bakugo and Fumikage Tokoyami at the Forest Training Camp via stealth and misdirection, though theatrical monologues sometimes undermine his efficiency. During the Shie Hassaikai conflict, he retaliates against Overhaul by compressing the yakuza leader’s arm after losing his own. Rising to lieutenant in the Paranormal Liberation Front’s Brown Regiment, he sacrifices his lower torso during the War to free allies from Best Jeanist’s bindings, enabling Tomura Shigaraki’s escape despite catastrophic injury. Post-war incarceration leaves him among the League’s few survivors. Blending flamboyance with pragmatism, he mentors junior members, shields comrades, and critiques hero society’s inequities. His philosophy of self-determined morality diverges from Harima’s altruism, yet his legacy persists through strategic contributions to the League’s operations and audacious sacrifices in pivotal battles.