My Hero Academia Season 4 — Complete Anime Review and Episode Guide
Anime: My Hero Academia (Boku no Hero Academia)
Studio: Bones
Season: 4
Episodes: 25
Aired: October 2019 – April 2020
Genre: Superhero, Action, Shonen
Based on: Manga by Kohei Horikoshi (Shueisha, Weekly Shonen Jump)
Introduction
My Hero Academia Season 4 is the season of a child and what it costs to save her. It is the season where Deku's heroism is tested not against a rival or a philosophy but against a specific, small, terrified person who needs someone to come for her — and against the enormously powerful man who has been using her as a resource. The Shie Hassaikai arc, which dominates the first two-thirds of Season 4, is one of the most emotionally demanding arcs in the entire series: slower in some stretches than the series' previous peaks, deeper in its character work than almost anything before it, and culminating in the moment that most fans consider the series' single greatest episode.
Season 4 is also the season of internships becoming real — of Deku working under the Number One hero Lemillion (Mirio Togata) and the Wild Wild Pussycats, learning what professional hero work actually looks like after All Might's retirement. The absence of the Symbol of Peace is felt throughout, and what fills that absence is not a single new symbol but the gradual emergence of a next generation — flawed, developing, genuinely trying — that the series has been building toward since its very first episode.
Story Summary — Detailed, Nothing Missing
Episodes 1–8 — Internships and the Introduction of Eri
The season opens with the internship arc, where Deku is placed with Sir Nighteye — All Might's former sidekick and a man who has the ability to foresee the future — under the umbrella of hero agency work connected to the investigation of Overhaul and the Shie Hassaikai organization. Sir Nighteye's initial assessment of Deku is cold and dismissive: he had a different candidate in mind for the succession of One For All, and Deku's selection by All Might against his advice is still a wound he has not fully processed.
The Nighteye-Deku dynamic is one of Season 4's most interesting relationship threads — an adult who is wrong about Deku in specific and understandable ways, whose wrongness is never dramatized as villainy but simply as a particular form of grief and displacement that makes it difficult for him to see what is actually in front of him. His eventual recognition of Deku — the specific quality of it, and what it costs to reach it — is one of the season's most affecting quieter moments.
Mirio Togata — Lemillion — is Season 4's most important new character and one of the most beloved supporting characters in the entire series. His Quirk (the ability to phase through any matter, making him simultaneously untouchable and extraordinarily difficult to move and breathe while in it) is among the most creatively designed in the series — a power that sounds like an absolute advantage and is actually extraordinarily difficult to use effectively, which means everything Mirio can do with it represents hundreds of hours of brutal training to achieve. He is also, as a person, one of the warmest and most genuinely optimistic characters in a show that has plenty of warmth and optimism. His relationship with Eri — his determination to come back for her after their first encounter when circumstances prevented them from taking her — becomes one of the season's emotional pillars.
Eri herself is introduced with complete care. She is a child who has been through things that children should never have to experience, and the series depicts the specific quality of her fear — the way she has been conditioned to accept harm as normal, the difficulty she has believing that anyone's care for her is genuine — without exploiting her trauma for spectacle. She is one of the most carefully handled child characters in shonen anime.
The investigation builds slowly in these early episodes — gathering intelligence about the Shie Hassaikai's operations, the nature of Eri's role in their Quirk-suppressing drug development, and the specific combination of authorities and hero agencies needed to mount a legal raid. This procedural dimension of hero work — the investigative, institutional work that precedes direct action — is something Season 4 depicts with more detail than the series has previously given it, and it makes the eventual action feel earned rather than arbitrary.
Episodes 9–15 — The Shie Hassaikai Raid
The raid on the Shie Hassaikai compound is the longest and most structurally complex action arc the series had produced to this point. A combined force of pro heroes and Class 1-A students (in an internship capacity) move through the underground compound while fighting Overhaul's associates — each of whom has a specific Quirk designed to obstruct the raid's progress.
The underground setting is one of the season's most distinctive visual choices — the labyrinthine architecture of the compound, which Overhaul can reshape with his own power, creates an environment that is never stable, never safe, and always potentially lethal in ways that the characters cannot fully anticipate. The visual design of the raid is among the season's strongest sustained work.
Mirio's fight against Overhaul while protecting Eri is the sequence that Season 4 will always be remembered for — and it is one of the most heartbreaking sequences in the entire series. Mirio fights at the absolute peak of his ability, using everything his extraordinary Quirk training allows him to do, while simultaneously ensuring that Eri is not further harmed. He is winning. And then Overhaul uses Eri — specifically, the Quirk-suppressing bullets produced from her biology — to hit Mirio, permanently erasing his Quirk. He continues fighting after losing his Quirk. He protects Eri until backup arrives. He is one of the best characters in the series expressed at his most completely himself in the worst possible circumstances.
Deku's arrival and the final confrontation with Overhaul — with Eri riding Deku's back and her Rewind Quirk unconsciously healing the damage that One For All causes to his body, allowing him to use the power at 100% without destroying himself — is the season's climactic sequence. Episode 23, which covers the final fight and Eri's awakening to her own power, is considered by a significant portion of the fanbase to be the single best episode of the entire series. The animation is extraordinary. The emotional content is overwhelming. The payoff of everything the arc has been building — Deku finally being able to use his full power, Eri experiencing what it feels like to be genuinely protected, Overhaul's defeat — lands with exactly the weight it should.
Episodes 16–21 — Aftermath and the Culture Festival
The aftermath of the Shie Hassaikai arc deals honestly with what happened — Nighteye's fate, Mirio's situation without his Quirk, Eri's recovery, and the institutional consequences of the operation. The series does not rush through this aftermath or move past it before it has been genuinely felt.
The Culture Festival arc that follows is the season's tonal shift — a deliberate lightening after the heaviness of the Shie Hassaikai arc, centered on Class 1-A preparing a musical performance for a school festival. The central purpose of the festival, from Deku's perspective, is Eri: she has never experienced a celebration, never experienced something meant purely for enjoyment, and bringing her to see something joyful is the specific, personal goal he is working toward.
The Culture Festival is one of the most beloved lighter arcs in the series because it earns its warmth. It is not simply a fun episode dropped into a serious show. It is the specific response to the Shie Hassaikai arc's devastation — the argument that the reason heroes fight through terrible things is so that small, specific moments of joy remain possible. Eri's smile at the performance is one of the series' most quietly triumphant images.
Episodes 22–25 — Endeavor and a New Number One
The season closes with the introduction of Todoroki's father, Endeavor, as the new Number One hero following All Might's retirement — and the immediate complication of that status. Endeavor is a deeply flawed person who has done genuinely terrible things within his family, and his ascension to Number One is not celebrated so much as simply noted as the mechanical consequence of All Might's departure. The final episodes set up the complex question of what it means for someone deeply flawed to hold the position of Symbol — and begin the extended arc of Endeavor's attempted redemption that will run through subsequent seasons.
Character Explanation
Mirio Togata (Lemillion)
One of the most beloved characters in the series for good reason. His warmth, his extraordinary capability earned through extraordinary effort, and the specific dignity of how he handles loss make him the season's most complete individual character portrait. His sacrifice is not meaningless — it buys time for Eri, it is consistent with who he is, and his response to it afterward is exactly what you would expect from someone who genuinely believes what he says he believes about heroism.
Overhaul (Kai Chisaki)
An extraordinarily effective antagonist whose villainy is specific rather than generic. His treatment of Eri is not simply cruelty — it is the expression of a specific worldview that reduces people to their utility, and the series uses him to ask pointed questions about what it means to treat a living person as a resource. His defeat is enormously satisfying precisely because his villainy has been precisely established.
Eri
Handled with complete care throughout the season. Her journey from terror to the first genuine smile is the season's emotional spine, and the series never exploits her suffering or uses it as mere motivation. She is a person, and the show treats her as such throughout.
Sir Nighteye
A fascinating supporting character whose function is partly to show that people who genuinely care about All Might can still be wrong in specific ways about specific things, and whose fate is one of the season's most quietly devastating moments. His change of perspective before the end is not a redemption arc so much as a genuinely human moment of recognition.
Theme and Highlights
The Small and the Specific: Season 4 is the first MHA season where the central stakes are not about the hero world's survival but about one child. The narrowing of scale from world-ending threat to one small person's freedom and wellbeing is not a diminishment of stakes but a clarification of what stakes actually mean. Eri's smile is worth everything spent to produce it.
What Power Is For: Deku using 100% One For All — something that has been impossible due to the self-destruction it causes — is only possible because Eri's Rewind can heal him. The power he has been unable to fully use becomes usable only when it is in service of protecting the specific person who makes it possible. This is the most direct expression of the series' argument about what strength is for.
Joy as the Goal: The Culture Festival's existence as a season arc — its refusal to be simply a fun breather episode — is the season's most thematically sophisticated choice. Joy is not a reward for surviving hard things. It is the reason hard things are survived at all.
Conclusion
My Hero Academia Season 4 is the series at its most emotionally direct and most emotionally expensive. The Shie Hassaikai arc demands a great deal from its audience — patience with its slower build, engagement with its most devastating moments — and rewards that demand with some of the finest individual episodes in the series' run. The Culture Festival provides the exhale that the Shie Hassaikai arc's inhale requires. And Eri's smile at the festival is the entire series' central promise, briefly and completely fulfilled.
FAQ
Q: Is Episode 23 really the best episode of the series?
A: Many fans consider it so, yes. The animation, the emotional payoff, the combination of Deku at 100% and Eri's awakening all combine into something genuinely extraordinary. Watch it and form your own opinion.
Q: Does Mirio get his Quirk back?
A: This is addressed in later seasons. No spoilers here.
Q: Is Season 4 slower than previous seasons?
A: The early build of the Shie Hassaikai arc is deliberately slower than the Sports Festival or the Hideout Raid. It is building toward something specific, and the slowness is structural rather than padding. Most viewers who engage with it find the payoff completely worth the patience.
Q: Where to watch?
A: Crunchyroll. Both sub and dub available.
Next: My Hero Academia Season 5 Review!
0 Comments