Nezu/Synopsis

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

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 Iida 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 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 upon himself to tell them the news. He explains that the recent surge of villains has caused the school to increase their 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
Mr. Principal, 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 criticize 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); Mr. Principal states that the situation would have been much worse if Tetsutetsu Tetsutetsu and Itsuka Kendo did not defeat the Sleeping gas villain. Mr. Principal 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. Mr. Principal, 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. Mr. Principal backs up Shota by saying that they are working with the Police Force to investigate Katsuki’s whereabouts and promises to retrieve him.