The following contains spoilers for My Hero Academia, available to stream on Crunchyroll.
My Hero Academia features some of the best character arcs, quirks, and relationships. For example, two of the main characters most known for their love-hate friendship are Deku and Bakugo. Both boys have endured so much together and learned a lot about themselves (and each other). Another friendship includes the one between Eraser Head and Present Mic, which dates back to their high school years.
However, of all the relationships and groups in My Hero Academia, U.A. High School's Big 3 is perhaps one of the most interesting groups. But exactly who are the Big 3, and why have they been given this title?
The Big 3
The Big 3 consist of three of U.A.'s strongest third-year students: Mirio Togata, Nejire Hado, and Tamaki Amajiki. Interestingly enough, the strongest does not necessarily mean physical strength (at least for two of the three). Rather, the extent of their quirks and their capabilities in using and controlling them makes them the Big 3. Their quirks also differ significantly.
My Hero Academia first introduces the Big 3 to Class 1-A when Aizawa, the class's homeroom teacher, brings them in to officially introduce them to his students. Though the Big 3 are equally strong, it is clear that Mirio Togata has taken the role of the leader due to his naturally outgoing and friendly demeanor.
Mirio Togata
Mirio Togata, or Lemillion, is one of the brightest characters in My Hero Academia. His strength and abilities are so powerful that All Might had once considered passing on One For All to him, but he changed his mind after meeting Deku. Mirio is also approachable and friendly, which is quite apparent from his appearance. He is bubbly, silly, energetic, and kind, which is almost at odds with his immense strength and interesting quirk, and permeation. Mirio's quirk allows him to pass through physical objects and change his body to one that can't be physically touched. In the case of the latter, if he were to get punched, the fist would go through his body. Along with this, Mirio is an especially strong, fast, and capable fighter. These qualities make him the perfect person to lead the Big 3.
In addition, Mirio's determination and overall optimism aides him after he loses his quirk when protecting Eri from a quirk-destroying bullet. He seems okay with being quirkless, despite spending the majority of his life training his abilities. He maintains his bubbly self throughout this time, indicating his true heroism. Much like Deku, Mirio is hero 'material' even when he doesn't have his quirk. Fortunately, Eri helps him regain his quirk. However, it's clear that Mirio, leader of the Big 3, has always been a hero. After all, heroes are born, not made.
Nejire Hado
Nejire Hado, who also goes by her hero name Nejire Chan, is one of the most powerful students, with abilities that can surpass Pro Heroes. Similar to Mirio, Nejire is quite bubbly, friendly, and blunt, perhaps a bit too much at times. This directness can be confused for rudeness, despite it not being Nejire's intention. After befriending Mirio and Tamaki, Nejire seemed to open up more.
Despite being described as cute and cheerful, Nejire is different when she is fighting. Her quirk, wave motion, allows her to send shockwaves at her enemy. However, because her quirk requires her to use her own energy, Nejire can become exhausted quite quickly. Along with using wave motion for offense, Nejire can also use it for defense. It's a versatile ability, even though it doesn't initially seem like it. Like Mirio and Tamaki, Nejire has excellent control over her quirk, making her one of the Big 3.
Tamaki Amajiki
Unlike his two bubbly and outgoing friends, Tamaki is shy, anxious, and an introvert. Unfortunately for him, as one of the Big 3, Tamaki must be the center of attention at times. As a result, his anxiety and discomfort cause him to frequently hide his face. However, he has admitted that he is grateful for his friendship with Nejire and Mirio because they push him to be better. Mirio is especially one of his closest friends and biggest supporters, particularly when Tamaki isn't feeling very confident (which is most of the time).
Tamaki, also known as Suneater, his hero name, is one of the strongest students in his school and all of Japan. Despite his capabilities and power, he admits that he doesn't feel like his quirk is anything special. His quirk consists of manifestation, which allows him to manifest the features of whatever he consumes. This also means he has to consider what he eats beforehand and use his quirk before his body digests his food completely. Much like his two close friends, Tamaki's power could surpass many Pro Heroes. However, his shyness and anxiety tend to hold him back. Yet, this doesn't mean that he does not try to overcome his internal obstacles.