U.A. High School
Neito shows great respect for his teacher, Vlad King. The first example of this is when Dabi attacks the extra lessons group's classroom during the Forest Training Camp; Vlad steps in to stop him from harming any of the students, to which Neito then praises his homeroom teacher's skill.
This admiration seems to grow by the time, because during the Joint Training Battle, Vlad takes the role of the commentator of the competition. His commentary takes on a very anti-Class 1-A attitude, reminiscent of that of Neito, which prompts several Class 1-A students to protest against him.
Not one Class 1-B student supports Vlad’s behavior as much as Neito; at one point he even begins imitating the exact same poses and attitude of his teacher.
In spite of him teaching his rival class, Neito doesn't shown any ill will to the teacher and shows him respect. Despite this, Shota has shown to feel annoyance as a result of Neito's behavior, as he scolds him before Itsuka can do it and tells him to behave.
Neito is obsessed with proving Class 1-B's superiority over Class 1-A, always looking for ways to increase Class 1-B’s prestige, which contrasts with his classmates, who in general they get along with Class 1-A students, and their rivalry is simply friendly. This difference in attitude causes some of them to being upset with how seriously Neito takes their rivalry with Class 1-A.
Despite this, and leaving aside Neito's histrionic tendencies, Class 1-B students have a good relationship with him. They care about him, and respect and value his leadership skills, plans and strategies. On the other hand, Neito always tries to help them, encourage them and consoles them when they feel they've messed up.
Neito and Itsuka are in the same class. Whenever Neito taunts or antagonizes the students of Class 1-A, Itsuka will step in, knock him out and apologize to the victimized class for his actions. Itsuka often criticizes Neito quite heavily, as seen when she tells him to stop provoking Katsuki Bakugo and stops him from picking a fight with Izuku Midoriya. In spite of this, Neito never seems to have any animosity, indicating the friendly atmosphere between them.
Itsuka doesn’t seem to bear much ill will towards Neito either, though it is clear that his outbursts get on her nerves. She turns him in during the scavenger hunt as a “perverse person” and taunts him about making enemies with Katsuki while patting his head.
Neito and Tetsutetsu are on good terms as classmates. Tetsutetsu also trusts Neito's judgment, along with most of Class 1-B, as he followed his plan to rank in the lower end of the Obstacle Course in the U.A. Sports Festival, and during the Cavalry Battle worked together with him to target Class 1-A's members. During the Cavalry Battle's start, the two also promised to not hold grudges against either regardless of the final result of the game. Much like Neito, it is revealed that he shares the fact he does not want his class to be upstaged by Class 1-A, despite Tetsutetsu being a lot more tame about it.
Monoma has an unhealthy obsession with Class 1-A. He's shown to be not just resentful, but envious of Class 1-A because of how they keep proving themselves in the field. For this reason, always take advantage of any occasion to undermine, underestimate and provoke Class 1-A. Class 1-A students usually ignore Monona's taunts, although some of them have outright wondered aloud about if something goes wrong with his mental state.
Neito sees Katsuki, along with the other members of Class 1-A, as arrogant, and feels that their popularity must be toppled. However, Katsuki doesn’t realise Neito bares any ill will until he takes his bandana in the U.A. Sports Festival’s Cavalry Battle and mocks him for being attacked by villains. This enrages Katsuki to the point that he stops chasing Izuku, his main rival and the person who’s bandana he has the most desire to take, in order to destroy Neito's team.
After repeated taunting, mocking and copying of his Quirk, in a fit of rage, Katsuki flies at Neito, jumping away from the rest of his team and taking all Neito's headbands, eliminating him and his team from the competition. With his defeat, Neito feels a certain disdain towards Katsuki, considering him too violent and underestimating his achievements and abilities as a hero. His classmates often try to advise him not to antagonize Katsuki.
Neito's opinion about Katsuki is so negative, that during fourth round of the Joint Training Battle, Neito expects that Katsuki will behave recklessly and allow his team to fail. However, after seeing him helping and saving his teammates, he's flabbergasted to see that Katsuki cared about his teammates and cooperated with them . When Class 1-B team is completely defeated, he can not deny Katsuki's development and his great teamwork.
As a student of Class 1-A, Izuku is a target of Neito's taunts and mockery. During lunch time, he intentionally bumped into Izuku’s head and sarcastically apologized to him, commenting that his head was big. He insults him and the rest of Class 1-A, saying that they want attention just like in the Sports Festival and when Izuku, Shoto Todoroki and Tenya Iida encounter Stain, before being knocked out by Itsuka twice.
They clash during the fifth round of the Joint Training Battle. Neito admits that he has to be on full guard since he's aware of Izuku's outstanding fighting technique. When they meet in battle, Neito tries to provoke him to respond, but fearing that he had copied Hitoshi Shinso's Quirk, Izuku remains silent. Beside this, Neito continues provoking Izuku, even to the point of sadistically taunting Katsuki in his involvement for ending All Might's career. Angered, Izuku aims his Air Force technique directly at his foe.
Before Izuku can ever release his attack, a mysterious black power bursts out of his arm and goes on a rampage. Thanks to the cooperation between Ochaco Uraraka and Hitoshi, Izuku could be stopped, and the mysterious power controlled. Neito takes advantage of their guard being down and ambushes Izuku. He manages to touch him and therefore copy his Quirk, and then attempts to activate One For All against Ochaco, but it doesn't appear to work, allowing Ochaco to defeat him and lock him up.
Even though Class 1-B loses the match, Neito still retains his old demeanor. Neito begins to rant about how his team didn't lose in terms of substance and reveals his newfound knowledge relating to Izuku's Quirk. He implies that he could easily beat Izuku if they were to rematch. Despite his disrespectful and harsh attitude during the battle, Izuku does not seem to hold any grudge against Neito, in fact he was worried about him when he tried to use the All For One, fearing for his physical integrity.
The next day, while trying to find more out about Eri's Rewind to help Shota, Neito reveals aspects of One For All that Izuku himself doesn't know. Neito says that he couldn't use Izuku's Quirk properly because, just like Eri's, it requires stored-up energy to work, and as Copy can’t take that it isn’t possible for him to use it.
Upon taking a first glance at the hero-in-training, Neito took an immediate liking to Hitoshi due to the latter's antagonizing of Class 1-A. Neito was happy that Hitoshi was willing to work on a team with him. He expresses empathy for Hitoshi, because like him, he grew up being derided for having a Quirk deemed unsuitable for becoming a hero.
When Izuku’s Quirk begins to go berserk, Neito’s first reaction after being forced to dodge is to immediately call out to Hitoshi in order to make sure that the latter is unharmed.
Even after being captured, Neito tries to help Hitoshi in his fight against Izuku. He shows this off by using the secret fourth Quirk, Nirengeki Shoda's Twin Impact, to throw Izuku off his balance and nearly give Hitoshi the opportunity to capture him.