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Something that Horikoshi laments is the fact he can't explore as much characters as he wants, showing interest in developing and talking more about all of Class 1-A and stating that at least for a while, all he can show is the character profiles. This sentiment becomes more pronounced as the series goes on, as Horikoshi keeps adding characters to his already large cast and doesn't expand them beyond their focus arcs:
Class 1-A
- In general, various students get considered this due to being Out of Focus, usually Shoji, Sero, Aoyama, Ojiro, Hakagure, Sato, and Koda. While some of them, namely Shoji, Aoyama, and Hagakure, would receive focus later in the story, many wish they had gotten more focus beforehand, and kept at a consistent amount.
- Although Tenya Iida did receive a character arc during the Field Training Arc, a lot of fans believe that his character peaked too soon, as he has only received occasional plot relevancy in subsequent arcs.
- Denki Kaminari has always been one of the most popular members of Class 1-A thanks to being a funny guy with a stylish design, along with awesome electric powers. Unfortunately, he has little to no impact on the plot, with the exception of the Provisional Hero License Exams. For the most part, he is a comic relief character who is regularly beaten up or embarrassingly humiliated in some way.
- An interesting variation of this is that some fans feel that Minoru Mineta, the resident Scrappy, had potential to be an interesting character due to his unique Quirk, distinct design, and self-esteem issues, and are disappointed that Horikoshi only put more emphasis on his perversion and jerkass behavior, but has yet to expand upon his non-perverted traits. His own character bio says that he's the second smartest person in Class 1-A, but we rarely see any hints of this or why he wants to become a hero in the first place when his two biggest character traits are "pervert" and "coward."
- Mina Ashido is one of the more visually striking members of Class 1-A, has a Quirk that is decidedly more villainous than would be expected from a hero in-training (Tokoyami's Quirk is similar, but it's effectively neutral until darkness comes into play) and she and Kirishima are the only members of Class 1-A besides Midoriya and Bakugo who knew each other prior to coming to U.A. Horikoshi has even said he's interested in doing more with her character. And yet, she's one of the very few Class 1-A students to not have had any sort of relevance to the main plot, or even a significant interaction with the main group besides Kirishima.
U.A. students
- Nejire Hado, despite being a part of the Big Three, hasn't a badass fight, or exploration of her issues and motivations like Mirio and Tamaki did during the Internship Arc, leaving her unexplored, despite being something the fans were very much expecting. This was lightly alleviated in the U.A. Cultural Festival Arc, where she received a sub-plot about her competition on the beauty pageant, though most fans agree that it's too little too late, not to mention it's annoying how the girl of the Big Three gets a beauty pageant instead of cool fight scenes.
- During the Joint Training Arc, several fans liked Setsuna Tokage for her attractive design, fun personality, and her powerful Quirk that had the potential to fully regenerate herself. Monoma hyped up Setsuna big time and believed that her team could defeat Bakugo's. She was also a recommended student just like Todoroki and Yaoyorozu. In the end, Setsuna was nothing more than a mere background prop to demonstrate Bakugo's Character Development and her team lost in a humiliating clean sweep.
- Although Tamaki Amajiki had a relatively important role during his debut in the Internship Arc, he was noticeably Demoted to Extra afterwards. In the Cultural Festival Arc, he barely has any dialogue and doesn't have any special moments, unlike Mirio taking care of Eri and Nejire participating in the beauty pageant. The same happens in the Paranormal Liberation War Arc, where he has the least screen time and the least participation of the Big Three, with his contribution being limited to a single page in the manga, while Mirio and Nejire were in the center of the main battle fighting against the League of Villains and the Nomus.
- During the Final Battle, Spinner leads an army of heteromorphs against the heroes to free Kurogiri. Of the heroes, only Present Mic, Shoji, and Koda are present, wasting the perfect opportunity to develop other Class 1-A heteromorphs like Sero or Ojiro, who have been absent during the war. This is made worse by the fact that class 1B have more heteromorphs than 1A, two of them (Bondo and Kuroiro) would have been ideal for the situation and would have much more easily stopped Spinner and his forcesnote .
Villains
- Magne is a Transgender villain with a unique Quirk and a backstory that would explain why she fits in well with the other social outcasts of the League of Villains. Unfortunately, she ends up being the first named character to die outside of a flashback, and is denied the opportunity for a Quirk powerup or additional backstory that the other members got in the Meta Liberation Army arc.
- Mr. Compress is a villain with Stage Magician theme and one of the most popular members of the League of Villains. Despite his charming demeanor, the former magician never had a dedicated fight scene. He is left Out of Focus in the Meta Liberation Army Arc while the rest of the League is given fights against the main members of the MLA. While he received some Character Development in the Paranormal Liberation War, his backstory of him as a descendant of the Uncanny Thief was hastily put together before he was captured late in the war.
- The Peerless Thief: Oji Harima was hyped as one of the great villains of the past, alongside historical All For One and Destro. However, while the latter two have had a huge impact on the story, the same cannot be said for Harima. As the manga progressed, readers were noticing that the Harima was completely irrelevant, with him being related to Mr. Compress everything important about the villain. This worsens when it is revealed in the ULTRA ANALYSIS Character Book that Harima had a Just Like Robin Hood philosophy, making it appear that Horikoshi had scrapped whatever storyline he planned with the character.
- The Meta Liberation Army members in the Paranormal Liberation War Arc, with the sole exception of Skeptic. Despite the fact that the arc is about a Villain Team-Up between the two organizations, the League of Villains gets virtually all of the spotlight. Re-Destro, Geten and Trumpet are Demoted to Extra, with only Skeptic getting to do anything important in helping with Dabi's broadcast and being the only one to escape capture. Curious was the only one to be straight-up killed off. On an organizational level, the Meta Liberation Army's goal to remove restrictions on Quirk usage the face of a world that strictly regulates it could have made for an interesting controversy, but that's never explored.
- Lady Nagant quickly became an Ensemble Dark Horse when she first appeared thanks to her interesting design, but despite getting her own battle with Deku in Dark Hero arc and having a motivation that makes her understandable, some feel that she was still a bit underdeveloped and that her character could receive a bigger focus in the story. Doesn't help that it was revealed in Vol. 32 extras that her backstory could last for even a volume instead of a few pages. Although she return during the Final Battle on the side of the heroes and has interaction with characters aside from Deku, some others agree that Nagant's participation was totally overshadowed by the most long-awaited return of Gentle and La Brava.
Side Characters
- A common complaint about the Internship Arc is how the girls never got to do much. While there were several chapters dedicated to the male characters Tamaki, Kirishima, Fat Gum, Rock Lock, Mirio and Sir Nighteye the female characters such as Ryukyu, Tsuyu, Uraraka and especially Nejire all had to share a single chapter and only one fight under the spotlight, a fight in which none of their characters are explored.
- The Magic Hero: Majestic is a character with interesting quirk who also tutored Yaoyorozu, one of the most outstanding students of Class 1-A, during her internship. Described before his introduction as a very powerful hero capable of becoming one of the top ten in the ranking of pro heroes, in the end he becomes only a Sacrificial Lamb to show the amount of deaths left by the Paranormal Liberation War and being Killed Offscreen.
- Star and Stripe is America's #1 Hero and an admirer of All Might with a standout design and Quirk, but suffers from a very late introduction to the series and is killed off via Heroic Sacrifice a few chapters later. Her battle with Tomura does last for longer than usual one chapter though and helps heroes to have more time to prepare for Final Battle, but her lack of interactions with any core cast members (including her idol All Might himself) make her feel like wasted potential.
