Atsuhiro Sako ( Sako Atsuhiro?), also known as Mr. Compress (コンプレス Misutā Konpuresu?), is a villain affiliated with the League of Villains and a member of the organization's Vanguard Action Squad. He is known for being one of the smartest villains in the world and acts as the brains of the League of Villains. He and the rest of his team serve as the main antagonists of the Forest Training Camp Arc.
Overall Abilities: Mr. Compress is a genius villain who thrives in a supporting role. He can act as the brains of an operation as well as act efficiently on his own. He single-handedly captured Katsuki Bakugo and completed the Vanguard Action Squad's mission.
Compress is a self-proclaimed master of deception, escapology, and illusion. He is clever enough to use his Quirk in creative ways and controlled enough to know the limits of his own power. Mr. Compress decided against fighting U.A. students and was almost fast enough to escape from them. Before getting caught, Mr. Compress was able to evade all of Shoto Todoroki's freezing attacks.
Compress is a master of stealth and often uses his Quirk on people before they ever knew he was around. He stole Katsuki and Fumikage Tokoyami before their classmates noticed and was only caught after he revealed himself. Mr. Compress is also a skilled tactician and uses his Quirk in creative ways to fool his opponents. He made the U.A. students believe they had rescued their friends by tricking them with compressed pieces of ice.
Enhanced Speed & Reflexes: Mr. Compress is incredibly mobile and agile. He easily outpaced pursuers in the forest by jumping across the tops of trees and even evaded Shoto's Giant Ice Wall move. He was also fast enough to catch Overhaul off guard.
Genius-Level Intellect: Mr. Compress considers himself an expert in deception and illusion. True to his words, he was able to restrain Katsuki and Fumikage without their comrades noticing, and he was spotted only when he decided to make his presence known. He also tricked his pursuers into thinking the marbles in his pockets were those of the two boys, while those were actually dummies he had prepared while dodging Shoto’s attack.
Stealth: Mr. Compress was able to activate his Quirk, requiring physical contact, on Katsuki and Fumikage while they were in a group of five people, among which was Mezo Shoji whose Quirk grants him enhanced senses, demonstrating excellent stealth abilities. Likewise, he incapacitated Snatch by circling around and touching him while the latter was fighting Dabi. Compressing himself allows him to be carried anywhere without being detected.
Compress (コンプレス Konpuresu?): Mr. Compress's Quirk allows him to "compress" anything in a spherical area into a small marble without actually damaging it. The weight of the target is reduced alongside them, making them very easy to carry. If used on a person, it effectively entraps them, terminating the fight instantly and allowing Mr. Compress to abduct them without difficulty. The Quirk can also be used on select body parts, maiming the target.