Debating My Hero Academia's Wildest Fan Theories

If you want to start a fight in the My Hero Academia fandom, just bring up fan theories. With over 100 million manga copies in circulation as of April 2024, and a global fandom that’s passionate and deeply invested, some theories have sparked endless debates, ship wars, and even calls for boycotts.

At number 5: The “Bakugo Is the Real Successor to One For All” theory. This idea launched after the release of My Hero Academia: Heroes Rising in December 2019. In the film, Izuku Midoriya attempts to transfer his Quirk, One For All, to Katsuki Bakugo during their battle against the villain Nine. For a few minutes, both fight wielding the same legendary power. Fans argued whether this moment was non-canon, a one-off for the movie, or an intentional foreshadowing. Some believed All Might had always meant for Bakugo to inherit One For All, with Izuku as the placeholder. Skeptics pointed out that in the manga, the transfer doesn’t stick, and Bakugo loses all memory of wielding the Quirk. The film’s production staff, including director Kenji Nagasaki and writer Yōsuke Kuroda, adapted the story with input from series creator Kohei Horikoshi. Horikoshi himself noted in interviews that elements of the movie’s plot were originally intended as a possible finale for the entire manga. This has only fueled the debate, with one side claiming the scene is a “what-if” scenario, and others insisting it reveals Horikoshi’s true intentions. The controversy endures because it challenges the core narrative of Izuku’s journey and Bakugo’s role in it.

Number 4 goes to: The “U.A. Traitor Is Toru Hagakure” theory. For years, fans suspected that someone within U.A. High School was leaking information to the League of Villains, especially after coordinated attacks on Class 1-A. Many pointed fingers at Toru Hagakure, whose invisibility Quirk made her the perfect spy. The theory grew stronger after the manga’s hints about a “traitor,” with discussions on social media and forums dissecting every panel involving her. Some even cited her lack of major storylines as “proof” Horikoshi was hiding something. However, the manga eventually revealed Yuga Aoyama as the traitor, not Toru. Yet, even after this reveal, some fans continued to believe there were multiple traitors, keeping the speculation alive. The argument gets heated because it questions both the trustworthiness of Class 1-A and the author’s approach to red herrings and misdirection.

Landing at number 3: The “Dabi Is Toya Todoroki” theory. This one was so widespread that it evolved from fan theory to confirmed plot point. Long before the manga revealed the identity of Dabi, fans analyzed his blue flames, his disdain for Endeavor, and even his facial scars. Many believed Dabi was actually Toya, Endeavor’s presumed-dead eldest son. The theory gained momentum after Dabi’s public broadcast exposing Endeavor’s abusive past and his own identity. When the reveal finally happened in the manga, some fans celebrated their “I called it!” moment, while others claimed the theory had been too obvious, accusing Horikoshi of telegraphing his twist too early. The debate isn’t about whether the theory was true—it’s about whether it was satisfying. Critics argue the reveal’s predictability weakened the emotional impact. Supporters counter that the story’s buildup and family drama made the payoff worthwhile.

Number 2: The “One For All Hazards Izuku’s Life Irreparably” theory. This idea took root as early as the original manga chapters, when Izuku’s body repeatedly broke under the strain of using One For All. Fans theorized that the Quirk’s power would eventually destroy him, no matter how strong he became. Some argue that the visible toll on Izuku’s arms and the repeated warnings from Recovery Girl and All Might foreshadowed a tragic ending. Others see the way the story handles Izuku’s injuries and his eventual mastery of the Quirk as a sign of hope and perseverance. The controversy centers around whether Horikoshi intended to punish his protagonist for wielding such a dangerous power, or if this was a symbolic return to Deku’s roots. The discussion splits fans who wanted a triumphant, all-powerful ending from those who see value in sacrifice and closure. In the manga’s epilogue, Izuku is shown as a U.A. teacher, and while the fate of One For All is left somewhat open, there is no explicit confirmation that he has become Quirkless again, which allows the debate to continue.

Finally, at number 1—the most debated fan theory in My Hero Academia: “All For One Engineered Shigaraki from Birth.” This theory exploded after the manga’s late arcs, where All For One’s manipulations are brought to light. In the story, Tomura Shigaraki is revealed to have been engineered by All For One to serve as his vessel, with All For One stealing his original Quirk as a newborn and replacing it with Decay. The family tragedy that defined Shigaraki’s childhood—accidentally killing his family with Decay—was orchestrated by All For One, setting his path as a villain from the moment he was born. Fans argue fiercely over the implications: some feel this robs Shigaraki of agency, making him a puppet rather than an antagonist with real motivations. Others see it as a dark commentary on generational trauma and the abuses of power. The theory becomes even more controversial because it was no longer just speculation; it became canon in the manga’s final arc, transforming how fans view the entire villain roster and All For One’s legacy. Whether this twist adds depth or undermines Shigaraki’s character remains one of the most polarizing debates in the fandom.

In the manga’s final chapters, the aftermath of All For One’s defeat and Shigaraki’s fate are explored in detail, with Shigaraki’s memories and motivations playing a central role in the climax. The way Horikoshi ties together the origins of the Decay Quirk, the Todoroki family’s trauma, and the legacy of One For All and All For One continues to fuel heated discussions about character agency, redemption, and the morality of power.