Nezu/Synopsis

History
Sometime before becoming U.A. High School's principal, Nezu was experimented on by human beings. This mistreatment led to Nezu developing a sadistic side to his otherwise polite personality.

Nezu eventually became the principal of U.A. and later hired Shota Aizawa as a teacher, who asked the principal for the ability to expel and re-enroll students, feeling that they should know the difference between self-sacrifice and throwing one's life away, so that they strive higher. Nezu was unsure about Shota's proposition, but accepted it.

At some point, he met Toshinori Yagi, who told him the secret of One For All, so Nezu suggested looking for a successor at U.A. High by giving him the opportunity to take up a teaching position at U.A.

Entrance Exam Arc
Nezu first appears among the judge's panel of U.A. faculty during the Entrance Exam's practical portion. He appears to be very excited when Izuku Midoriya destroys the gigantic villain bot in a single punch.

U.S.J. Arc
U.A. is stormed by reporters seeking information about All Might's teaching position. After the Police Force escorts the media off the property, Nezu and other teachers investigate the breach in the security barrier. They ponder whether a reporter was responsible or if a villain possibly penetrated their defenses. Nezu suggests that this was a possible declaration of war.

Nezu catches All Might trying to prematurely join Shota Aizawa and Thirteen as they instruct rescue training at the U.S.J.. He lectures All Might about his proactive nature and how resolving criminal incidents has limited his ability to join the instruction. All Might asks to be excused so he can go to the U.S.J., but Nezu knows he would have to return almost immediately to conceal his identity and asks him to stay. Nezu pours them both cups of tea and begins monologuing about teaching philosophies.

Nezu joins his fellow faculty members as they follow Tenya Ida to the U.S.J.. Following the assault on the U.S.J., Nezu is present for a meeting to discuss the attack and its implications regarding the League of Villains and its leader, Tomura Shigaraki. Nezu suggests that Tomura is being guided towards villainy in the same way U.A. students are being guided towards heroism.

Final Exams Arc
Prior to the Final Exams, Nezu holds a meeting with his faculty to discuss changing the format of the practical exam. He presents the idea that students should fight the teachers in teams of two in order to push them and make them as strong as possible. He also mentions that this is all in preparation of the rise of villains that's to come in the wake of Hero Killer Stain.

When the time comes to inform the students of the change, Nezu jumps out of Shota's scarf and takes it upon himself to tell them the news. He explains that the recent surge of villains has caused the school to increase its training methods and from now on, U.A. students will take part in real life battle simulations starting with Class 1-A. He informs them all that the students will be tested by facing off against the teachers, shocking the students. Nezu is matched up against the pair of Mina Ashido and Denki Kaminari because their grades have been poor.

At the start of their battle in Ground Gamma, Nezu commandeers a crane with a wrecking ball attached to it. His Quirk gives him such high intelligence that he can predict the chain reactions of everything he destroys. This causes a lot of trouble for Denki and Mina, who struggle to find a path to the escape gate. Nezu drinks a cup of tea, noting that making decisions is rudimentary for him. He notices his opponents have not deduced his strategy and laughs maniacally at them from afar.

Denki and Mina try to run for the escape gate, but the principal stays one step ahead of them the entire time. He destroys all of their paths to the escape gate except for one. Even so, Denki and Mina run out of time before they ever even realize what Nezu was doing. They fail the test and prove their weakness lies in facing intellectual villains.

Hideout Raid Arc
After the League of Villains attacked the training camp, hospitalizing several students and kidnapping Katsuki and the Pussycat member Ragdoll, Nezu holds a meeting with the U.A. staff. In the meeting, he discusses the consequences of Katsuki's kidnapping and potential turn to villainy. In response to Hizashi's suspicion of a mole, he reassures the staff that he trusts all of them.

Nezu, along with Shota Aizawa and Vlad King, appears in U.A.'s public apology broadcast where they apologize to society for their shortcomings. However, society still criticizes U.A. for being unable to protect the students and criticizes their security measures for not ensuring the safety of the students.

Shota tells the reporters that he decided to let the students fight due to not knowing the full situation in order to prevent the worst possible situation from happening and as a result, no students were killed (which is the worst possible outcome in his opinion); Nezu states that the situation would have been much worse if Tetsutetsu Tetsutetsu and Itsuka Kendo did not defeat the Gas villain. Nezu also says that they are seeing to the well-being of their students and have not seen any signs of emotional trauma.

The reporter asks the principal if U.A. had already failed in securing the students' well-being due to not checking Katsuki's mental instability and his "villain-like" performance during the U.A. Sports Festival. Nezu, Vlad King, and Shota know that the reporter is purposely provoking them with this particular question. Shota answers that out of all the students, Katsuki was the one who showed that his conviction to be a Hero was the strongest and believes the villains to be foolish if they think that they can turn Katsuki into a villain. Nezu backs up Shota by saying that they are working with the Police Force to investigate Katsuki's whereabouts and promises to retrieve him.

In the League of Villains' hideout, Tomura enjoys watching the criticism that the U.A. staff is suffering for their actions. However, Katsuki refuses to join their ranks and, encouraged by the words of his teacher Shota, rebels and trying to escape. At that moment, All Might, Kamui Woods, Edgeshot and Gran Torino assault the lair and quickly restrain the League of Villains'; Mr. Compress realizes that U.A.'s press conference was just a diversion so that the League of Villains would lower their guard. It seems that the rescue operation has ended successfully, but All For One decides to intervene. Using the Quirk Warping, he teleports Katsuki and the League to his lair, while sending several Nomus to face the Heroes and the police forces.

Knowing where Katsuki and the others had been teleported, All Might quickly heads to the place after getting rid of the Nomus. Once there, thanks to Izuku, Tenya and Eijiro, Katsuki is rescued, but All For One uses Warping again to allow the League to escape, leaving only him to face All Might, starting a battle between them that is televised to the whole country. Nezu, along with Vlad King and Eraser Head, watches the horrifying broadcast of All Might's bout. After an intense fight, All Might manages to defeat All For One, but consequently loses One For All forever.

Several days later, All Might meets with Nezu alongside Vlad King and Eraser Head. Nezu thanks All Might for his victory against All For One as many lives were saved thanks to his intervention. Even though All Might will be continuing as a teacher, Nezu points out that since he is no longer able to fight, the parents of the U.A. students, as well as society, are anxious and worried about the safety of the children. Nezu reiterates that they must instill faith and confidence in heroes.

Sekijiro Kan agrees with Nezu and vows to nurture, raise, and protect the students more strongly than before. Nezu decides that now is the time to implement a plan of his for quite some time. Nezu and Sekijiro will visit the parents of Class 1-B while Shota Aizawa and All Might will visit the parents of Class 1-A as part of the plan. The plan Nezu wants to implement is the transition of U.A. to a boarding school.

Provisional Hero License Exam Arc
Following the intense villain attacks toward U.A. students, Nezu transforms U.A. into a boarding school in order to protect the students. The Heights Alliance is built in just three days. As the students prepare to start their new lives at the new Heights Alliance dormitory, Nezu overlooks the new dorm buildings. They are not only for student safety, but also to keep an eye on the supposed "traitor" in their ranks. Nezu feels guilty for doubting his colleagues and students but his top priority is to protect the students. He decides that U.A. must direct its students to a hopeful and brighter future now that All Might is no longer the Symbol of Peace.

Several days later, after the Provisional Hero License Exam, all U.A. students attend the opening ceremony. There, Nezu introduces himself. After talking about his diet and lifestyle going out of sync, he states that the reason for his lifestyle becoming inadequate is due to the incident that took during the summer break. He talks about All Might's retirement and the negative effect it will have on society and the Department of Heroics will likely see the most striking effects. Nezu tells the Second and Third years that because of the Hero Program they are engaged with, they must have an awareness of the crisis and conduct themselves accordingly.

Nezu apologizes for bringing down the mood, but the Heroes are dealing with the situation to the best of their abilities and he would like nothing more than to develop them into individuals who will take over their efforts. Nezu ends his speech by saying that whether they are in the Departments of Heroics, Support, and General Education and even the staff of U.A., they must not forget that they are the successors to the Hero society.

U.A. School Festival Arc
Everyone at U.A. High is preparing for the U.A. School Festival. Due to recent incidents, the rising number of villains and the destabilization of the Heroes, Nezu receives the visit of the Police Force's Commissioner General to persuade him to curtail the School Festival. The Commissioner General believes that if an attack occurred on the School Festival, it will make preventing the next attack impossible.

The Commissioner General requests Nezu to cancel the School Festival altogether, wanting to quietly focus on training the next generation of Heroes. Nezu agrees that he has a point but refuses to do it, believing the School Festival is a necessary time for the students, arguing that it's precisely in difficult times when students need the festival.

Nezu begs the Commissioner General to let the festival go on since he does not want to count on a dark future. Nezu tries to convince the Commissioner General, assuring him that security measures will be increased and some of the teachers will patrol U.A.'s premises. The Commissioner General finally agrees to his request, but imposes on him as a condition that they immediately suspend all activities if alarms sound, even if it is a false alarm.

During the following weeks, at the request of Izuku, Shota asks Nezu if Eri, a little girl whom Izuku had rescued during the Shie Hassaikai Raid, can attend the Festival. Izuku believes that, after months of suffering at the hands of Overhaul, the Festival will help Eri overcome her trauma. Nezu gives them his permission.

Finally, the School Festival carries out without any incidents interrupting it and ends up being a huge success that helps to raise the morale of everyone.

Joint Training Arc
The next day after the Joint Training Battle, in the Conference Room, the teachers make the final decisions for Hitoshi Shinso to be transferred to the hero department. They decide that it will definitely be happening. Nezu tells the others that he will take care of the paperwork and asks them to focus on the teaching.

My Hero Academia: Heroes: Rising
Sometime during the fall, Yokumiru Mera meets with Nezu and All Might at U.A. High School, explaining to them about the Hero Work Recommendation Project, which is dedicated to helping train the new generation of heroes after All Might's retirement.

Endeavor Agency Arc
A few days before winter break, Nezu holds a meeting at the U.A. Conference Room. Nezu notifies all the U.A. teachers that the Hero Public Safety Commission has requested that from now on, every hero course student is required to train by attending Hero Work-Studies.

Paranormal Liberation War Arc
Shortly after the Paranormal Liberation War, Nezu received a few phone calls from the government to convert more of U.A. High into a sanctuary for families of students in the hero course to protect them.

Dark Hero Arc
In the aftermath of the Paranormal Liberation War, All For One has escaped from Tartarus, and proceeded to break into several more maximum security prisons, liberating the inmates. Due to the chaos inflicted by Gigantomachia and the mass breakout of prisoners, the whole country entered a state of total chaos and anarchy. In addition, many heroes resigned and called it quits because of the massive criticism of their work, and the destruction spreading unchecked. As the result of the destruction and chaos running rampant across the country, Nezu has begun to convert the U.A. High into a sanctuary shelter to house the civilians. He also became aware that Izuku had gone rogue and left U.A. to work alongside All Might and the Top Three Pro Heroes to search for All For One and Tomura.

Soon after, Class 1-A came to his office in order to confront him about Izuku's whereabouts. After hearing them out, Nezu contacts Endeavor to meet him in his office, unaware that all of Class 1-A are present to confront him. Nezu informs Endeavor that he heard what they had to say and decided there was room for discussion since he is constantly getting updates himself. After Class 1-A has confirmed their answers from Endeavor, he decides to hand the students his GPS satellite phone which can pinpoint Izuku's exact location. All of Class 1-A vow to follow Izuku wherever he goes, and no matter how much responsibility that comes with One For All, they consider him their friend, and they won't let him walk such a troublesome path all by himself.

Endeavor tells the students that the outside world is messed up right now but Nezu reassures them that they are ready. He says that he agreed to let Izuku team up with the Pros since he didn't want to return to U.A. and that the villains were targeting him. But he reveals that he can return to school, since the minute they sent out the acceptance notifications, they all became students they will protect. Endeavor asks about the civilians and Nezu tells Endeavor that the designated evacuation areas weren't only chosen based on area, and that the school has reinforced their security "U.A. Barrier" since the Culture Festival. He assures the students that Izuku will be fine if he comes back, so they can go help him.

Tenya then asks Nezu how they can provide concrete evidence that the people taking shelter at the school will be safe when Izuku comes back, in addition to the U.A. Barrier. Nezu tells them Izuku is the most valuable asset the Heroes have to fight back so having him at an unprepared shelter would be a huge risk. However, he informs them that U.A. is equipped with the one of the most advanced defense technology for that reason, even being on par with Tartarus.

Momo reminds him that Tomura had just destroyed Tartarus, but Nezu then tells everyone that after Tomura attacked the school last year, he put considerable thought into how to better prepare, and he ended up adding a few touches to the system of his own design. The reason why Nezu feels so confident that if U.A. was to be attacked, no one would be harmed, is because according to him, U.A. can travel, much to their shocking surprise. Nezu explains that each section of the school is like a game board, each equipped with mechanisms that will transform it into an underground emergency shelter. Then, those shelters will enter a network underground and move in any direction.

Nezu explains the system is still at risk of crumbling, so he fortified the ground with about three thousand layers of Bulwark plates, and should the system detect any unusual activity, the connecting pillars will unlock and render each plate mobile, thereby delaying the attack and allowing the shelters to speed off to safety. He also adds that Shiketsu High was the first to fortify their school system after Camie was impersonated by Himiko, and is just one of several hero schools with the safety precautions needed for sheltering they could rely on if need be, shocking the students considering how far the two schools are.

Fumikage, knowing that the counter-measures were to combat Tomura's increased Decay, wonders how he managed to anticipate this since it was built around the time of the School Festival, with Nezu saying it was just his intuition, and that he paid for all of it. The students are left amazed at how expensive it all was but Endeavor adds that Nezu's contributions to Quirk morality education has earned him worldwide renown, and his work is still continuing. Nezu says that intolerance and a lack of understanding make the one step towards coming together always seem far away, but he believes a sound argument can be made for letting Izuku return to the school, and entrusts the students to handle the situation with their full power.

When Izuku finally returns to the heavily fortified U.A., he and Class 1-A are confronted by a angry mob of civilians taking shelter in the school, protesting his return as a trap to lure the villains inside. With no one seemingly listening to reason, Ochaco floats her way over the crowd and jumps up onto the U.A. building with a megaphone, admitting that his power is what the villains' desire because they know it is the only thing that can stop them, but he has gone through so much while on the outside. She begs for everyone to take a closer look at him for he wishes to fix everything despite knowing he could be attacked at any minute.

When the people start calming down, Nezu was astonished of Ochaco's speech pacifying the crowd. In his mind, he thought of how a single step is always hard to take, but he believes if it is taken, it will carve a path for the ultimate hero to stand up: one that can even surpass even All Might himself.

As Class 1-A helps with the civilians and Izuku is escorted inside, Nezu communicates to Shota, telling him his class managed to do well, to Shota's delight. Nezu asks about the status of Kurogiri, who states that they've had no success in getting through to him yet, with Nezu reminding that without Oboro Shirakumo regaining consciousness, they would never have gotten as far as they have, meaning there is still hope. Shota asks about the countermeasures regarding Himiko, with Nezu saying that since they've figured out how much blood she can absorb and how long her transformation lasts, they only let in the evacuees after a certain amount of time to be sure.

U.A. Traitor Arc
While Nezu continues to do his duties, he and the other U.A. staff learn the devastating news that Yuga Aoyama from Class 1-A and his family were captured by Izuku and he is revealed to be the U.A. traitor Present Mic mentioned a year ago, responsible for the U.S.J. Incident and revealing the location of the Quirk Training Camp. In the U.A. A.V. Room, the Aoyama Family are interrogated by All Might, Detective Naomasa, and the U.A. staff, learning Yuga was Quirkless and received his Quirk about 10 years ago from All For One, so his family was forced into his debt. Nezu, knowing how strong of the bond between Class 1-A students is, asks Class 1-A to please let themselves leave for some time. However, all of Class 1-A had already heard the news and are devastated, bluntly refusing to back down.

After interrogating them on information regarding All For One, Izuku speaks up as he recognized Yuga's troublesome situation and had no malicious intentions in his actions, so wants him to help them and prove he can still be a hero. The rest of the class believes this as meaning they can use Yuga to deceive All For One, but Naomasa reminds them that it is still very unlikely that could work. Just then, Shota, listening in on a tablet, informs everyone that he has an idea, which they all listen to after covering the Aoyama Family's ears. Nezu says that it seems possible, and All Might adds that it'll be up to how well "he" can handle it, as Naomasa escorts the Aoyama Family back to their HQ, telling everyone not to say a word to anyone else about the plan. With everything settled, the police takes Yuga and his family away for further investigation, leaving Class 1-A to look on sullenly.

Enraged over Yuga's betrayal, Class 1-A relentlessly searched for All For One, and they return for a break back at Heights Alliance from their search efforts. All Might, Naomasa, and Nezu burst into the dorm, to inform them all about their secret finalized plans for the upcoming Final War. They explain to the class of their plans to deceive All For One, reminding them how unlikely it is they'll be able to track them down in their search, however, this works to their benefit as it allows them to draw him out by getting him to loosen up. Naomasa explains how they assume that All For One is using Search to monitor everyone, and everything they've done since Izuku returned will make him believe that they're being exhausted, which will allow them to catch him off guard, and utilize Shota's plan of having Yuga choose the location to lure him out.

Knowing that All For One may have ways to detect a lie, they will have Hitoshi Shinso come forward to brainwash the Aoyama family in deceiving All For One. Nezu adds he's already gotten permission from acting Hero Public Safety Commission President Yokumiru Mera since he doesn’t have his Provisional Hero License yet.

The next day, Nezu announces to the civilians that Tomura will make his big move in 4 days, with Class 1-A giving their thanks to everyone at the entrance, and Izuku saying he's had more than enough time to clean himself up, with them all ready to head back out. One of All For One's subordinates laughs at Izuku for making things easy for them by leaving on his own, and now their mission is guaranteed to "succeed". Nezu watches Class 1-A each say goodbye to their family members and the civilians before moving out of U.A. for good.