Atsuhiro Sako

Atsuhiro Sako, also known as Mr. Compress (コンプレス), 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.

Appearance
Mr. Compress is moderately tall and skinny. As Mr. Compress, he wears gloves, an azure bolo necktie, a large and fancy overcoat, boots, and a top hat with a feather. Under the overcoat is a black waistcoat and a red shirt. Following the events of the Internship Arc, he acquired a robotic prosthetic arm.

Mr. Compress's face is covered by a balaclava and a white mask with black motifs which he changes approximately at every turn of arc.

In the Forest Training Camp Arc, the mask bears large, stylized eyes and teeth, exhibiting what appears to be a grin.

In the Hideout Raid Arc, the top half of the mask is painted with parallel vertical lines, while the lower half has diagonal lines that meet along the vertical axis of the mask.

At the end of the Hero License Exam Arc and at the start of the Internship Arc, the mask Mr. Compress wears sports a black dot at the center of the upper half, while the lower half bears oblique lines that seem to converge towards it.

During the Internship Arc, he dons two more masks: one which bears resemblance to a frown, and plain one with a black dot where each of Mr. Compress's eyes would be.

Personality
Mr. Compress is a talkative, humorous person with his allies and enemies alike. He seems to value the possibility of choosing one's beliefs, insisting that U.A. High School's students have had their values hammered into them by others. Although he claims to be good at running away, he expressed disappointment in the abilities of the Hero cadets he met. He also trusts his own judgment, kidnapping a second target beside the one he was assigned to.

History
At some point of his life, Mr. Compress worked as an entertainer.

Forest Training Camp Arc
Mr. Compress appears on a tree branch and reveals that he used his "magic" to take Katsuki Bakugo by turning him into a marble. Mr. Compress states that the Heroes do not deserve someone of Katsuki's caliber and notes that Katsuki will shine even brighter on the villains' side. Izuku Midoriya demands that he give Katsuki back.

The Bakugo Escort Squad, Ochaco Uraraka, and Tsuyu Asui come face to face with Mr. Compress who has kidnapped Katsuki. Izuku demands that he gives Katsuki back because he would never work with villains due to being his own person. Shoto Todoroki freezes the tree but Mr. Compress evades Shoto's attack. Mr. Compress states that they are attacking the training camp to make a point, that they are proving there is not only one perspective at which to look. Mr. Compress criticizes the U.A. students' for having their perspectives and values chosen for them, displeased that there is no free will. Mezo Shoji realizes that Fumikage Tokoyami has also been taken. Shoto surmises that the villain sneaked up behind them and kidnapped Katsuki and Fumikage. Mr. Compress explains that his mission was to capture only Katsuki, but after seeing Fumikage overpower and defeat Moonfish so easily, he decided to kidnap Fumikage as well because of his powerful Quirk and notes that he will prove to be useful. Shoto hands Kosei Tsuburaba to Ochaco. After doing so, Shoto uses his Giant Ice Wall attack in an attempt to immobilize Mr. Compress. However, Mr. Compress evades and apologizes for only running away and deceiving, admitting that is what he is good at. Mr. Compress informs the Vanguard Action Squad that their target has been captured; he tells his fellow villains that the mission is done and states that they have five minutes to rendezvous at the "collection point." Shoto refuses to allow them to succeed in their mission and prepares to chase after him.

Mr. Compress begins escaping and is unimpressed with the Hero cadets. Suddenly, he sees Izuku, Mezo and Shoto flying towards him. After Ochaco deactivates her Quirk, Izuku, Mezo and Shoto land on top of Mr. Compress and smash him into the ground near the Vanguard Action Squad's rendezvous point.

Dabi asks Mr. Compress to dodge and launches his flames. Mr. Compress uses his Quirk to compress himself to dodge the flames while Mezo and Izuku are injured by Dabi's flames. As Twice and Himiko Toga deal with Izuku, Mezo and Shoto, Mr. Compress decompresses himself and approaches Dabi, preparing to give the captured Fumikage and Katsuki to him. However, he searches his pocket and is unable to find the marbles containing the targets; Mezo reveals that he took the marbles from Mr. Compress immediately after they landed on the ground. Dabi calls Mr. Compress a fool, but the magician calmly tells him to wait and see what happens.

Soon, Kurogiri arrives to retrieve the Vanguard Action Squad. After Himiko, Twice, and Nomu teleport away, Dabi and Mr. Compress also prepare to leave, although Dabi is distressed that they do not have Katsuki. However, Mr. Compress relieves Dabi's concern by revealing that the compressed Katsuki and Fumikage were in his mouth all the time and the marbles Mezo stole were Shoto's compressed ice. Mr. Compress puts his mask back on while explaining that he wanted to give the young Heroes a sense of false hope and is satisfied by it as well as his flaunting which he considers a bad habit. Mr. Compress slowly enters Kurogiri's portal after bidding farewell. Having overheard what is happening, Yuga Aoyama takes action and fires his Navel Laser at Mr. Compress's face, which breaks his mask and causes him to spit out the marbles containing Fumikage and Katsuki.

After grabbing Katsuki's marble form, Dabi orders Mr. Compress to deactivate his Quirk, which frees Fumikage and Katsuki. Mr. Compress, Dabi and the captured Katsuki teleport away from the training camp.

Hideout Raid Arc
After watching the video clip about U.A.'s public apology, Tomura understands why society is criticizing U.A. for their failure and that is because the current Hero society is not just. Spinner agrees that the current Hero society is not just since the modern Heroes are only doing their job for compensation and not out of selflessness. Tomura explains that the League of Villains are fighting for a just society and intends to win this battle. Tomura orders Dabi to remove Katsuki’s restrains, although Dabi is unsure since Katsuki might attack; Tomura wants to treat Katsuki as an equal and is aware that Katsuki knows he has no possibility of winning. Dabi has Twice remove the restrains. As Twice removes the restrains, Mr. Compress apologizes to Katsuki for forcibly kidnapping him and explains that the League of Villains are not just a group of hoodlums perpetuating crimes nor did they casually abduct him; he goes on by saying that everyone in the League of Villains is shackled by the current society and hopes that Katsuki understands their discrimination.

Katsuki’s restrains are removed. As Tomura approaches Katsuki, Katsuki attacks Tomura with his Explosions. Katsuki tells the League of Villains that it is pointless to try and make him change his mind as he has already been won over by the way All Might looks when he wins. Katsuki says that from the beginning he has dreamed of becoming a Hero and surpassing All Might and nothing they say will change that.

Katsuki tries intimidating his captors, but Mr. Compress along with the rest of the Vanguard Action Squad are not intimidated; Mr. Compress states that if Katsuki was moronic, he would have listened to them and is disappointed in Katsuki's decision to go against them.

Tomura orders Mr. Compress to use his Quirk on Katsuki again. Mr. Compress is impressed with Katsuki's stubbornness. Before he has the chance to, All Might breaks in with Kamui Wood swinging in and restrains Mr. Compress along with the other League of Villains with his Lacquered Chains Prison. Mr. Compress realizes that U.A.'s public broadcast apology was just a diversion to catch him and his fellow villains off guard.

Out of nowhere, Nomus appear from mysterious back liquid which takes the Pro Heroes off guard. Mr. Compress along with the League of Villains are teleported by the mysterious black liquid to the League of Villains' destroyed warehouse where All For One is.

All For One forcefully activates Kurogiri's Quirk which creates a portal for the League of Villains to escape through. Mr. Compress uses his Quirk on the unconscious Dabi and tells Tomura that they need to leave. Seeing that Katsuki won't go with them willingly, Mr. Compress along with Twice and Himiko battle Katsuki but Katsuki fends them off with Explosions.

After Katsuki is rescued by Izuku, Tenya and Eijrou, Mr. Compress along with Magne and Spinner hatch a plan to recapture Katsuki. Magne magnetizes Mr. Compress and Spinner pushes him, causing Mr. Compress to fly at Izuku's group. Suddenly, Mount Lady uses Titan Cliff and intercepts Mr. Compress, which causes them to smash into each other, preventing Mr. Compress from getting to the students. Mr. Compress falls to the ground and becomes unconscious due to Mount Lady's attack.

Mr. Compress along with Tomura and the Vanguard Action Squad are forcefully magnetized by Magne's Quirk courtesy of All For One; Mr. Compress is sucked into Kurogiri's Warp Gate and teleported away.

Internship Arc
Overhaul enters the League of Villains hideout, but is unimpressed with Tomura and his members as well as his unclean hideout. Overhaul explains to the League of Villains that with All For One's downfall, someone will eventually become the next ruler of the underworld. However, Tomura replies that he will become the next underworld ruler after he gather more members and crush the current Hero society. Overhaul asks Tomura if he has a plan, to which Tomura responds that he thought Overhaul wanted to join them. Overhaul is disappointed that Tomura doesn't have a plan to achieve his objective and laments that he wasted the potential of Stain, Muscular and Moonfish. Overhaul reveals that he wants the League of Villains to join him so that he can teach them the proper way to run an organization and use them to gain financial capital so that he can get one step closer to becoming the next underworld ruler.

As Tomura orders Overhaul to leave, Magne rejects this proposal and magnetizes Overhaul, bringing him into Magne's range. Magne hits Overhaul on the head with her weapon, to which Overhaul responds by touching Magne. Overhaul's physical contact causes Magne to blow up, much to the League of Villains' shock. Overhaul blames the League for throwing the first punch and dislikes the blood running down his face. Mr. Compress charges forward and touches Overhaul but his Compression Quirk does not activate due to being shot in the arm. Overhaul is enraged that he has been touched and completely disassembles Mr. Compress's left arm. Overhaul then calls his subordinates, who come crashing in. Seeing that both of their organizations have suffered casualties with the deaths of their respective members, Overhaul ceases fighting and leaves, wishing to talk with Tomura again after he has calmed down.

With the help of Twice and Himiko Toga, Mr. Compress and the League of Villains find and apprehend the police van escorting Overhaul. Sand Hero "Snatch" confronts them but after a brief skirmish, Mr. Compress compresses him into a sphere with some of Dabi's flames. The van transporting Overhaul crashes after hitting a boulder Mr. Compress threw into the road. Tomura and Mr. Compress confront Overhaul and tell him how much they hate him. Mr. Compress agrees with the statement and compresses part of Overhaul's left arm, severing it at the wrist as an act of revenge. Tomura decays Overhaul's right arm before cutting it and taunts the powerless yakuza about how he wanted others to lose their Quirks but now he himself is one of them. Overhaul is left speechless while the League of Villains walks away from the wreckage with the Quirk-Destroying bullets.

Quirk and Abilities
Compress (コンプレス): 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.

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 Mezou, 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.

Enhanced Speed & Reflexes: Mr. Compress is endowed with quick reflexes and impressive acrobatic skills. He was able to dodge Shoto's ice, even when the latter uses his Giant Ice Wall, with little effort, despite being on top of a tree. He is also very fast, quickly distancing himself from the U.A. students by running on the treetops.

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 Todoroki's attack.

Shigaraki Tomura
Mr. Compress appears to have a sense of loyalty to Tomura similar to Kurogiri. His actions and instructions during the battle between All Might and All For One were thought out for Tomura's interest.

After his teammates escaped, Mr. Compress was seen alongside with Tomura while the other members were separated elsewhere.

League of Villains
Mr. Compress seems to genuinely care for his teammates. He does not view his teammates as merely hoodlums who commit acts out of just evil purposes. Rather, he seems to understand their circumstances and can relate to their situations.

During the battle between All Might and All For One, he took charge of the situation for the best interests of his teammates: instructing appropriate actions for Tomura and compressing Dabi in order to carry him to safety.

After the battle, he made sure that the members regularly contacted one another to make sure none of them are caught and puts them in danger.

Trivia

 * In one panel of Chapter 156, the chin portion of Mr. Compress's mask is painted black, whereas in all other cases it is white.

Quotes

 * (To several U.A. students) "We're just a bit fanatical when it comes to our values. All we wish is to show him that there are other ways. Because you kids today... you have your values chosen for you."