My Hero Academia Confirms a Villain's True Dark Past With a Brilliant Twist

Summary Overhaul's quirk is revealed to be the quirk factor of Shigaraki's Decay.

Overhaul was in one of Dr. Kyudai Garaki's orphanages as a child.

Chisaki's dark origin links to his experiments and twisted ethics.

My Hero Academia’s recent chapters revealed the origin of Shigaraki Tomura’s quirk: All For One took Tenko Shimura’s unknown quirk factor passed down from his parents and gave him Decay, an incomplete duplicate of the quirk of one of the children’s in Dr. Kyudai Garaki's facilities, who turns out to be Kai Chisaki, aka Overhaul.

Overhaul, the quirk of Kai Chisaki, the main villain in My Hero Academia's Shie Hassaikai arc, allows him to deconstruct and reconstruct anything he touches with his bare hands. This shares many similarities with Shigaraki’s Decay: both abilities are very powerful, activated directly with their hands, and can destroy anyone with a single touch.

This is not just a coincidence, chapter #419 showed that the quirk factor duplicated by Dr. Garaki for Decay came in fact from Chisaki. However, Decay was engineered by the doctor to leave only the destructive half by taking away the ability to reverse the effects.

Related Big My Hero Academia Twist Gives One Villain the Series' Darkest Backstory Yet Chapter 419 of My Hero Academia reveals the truth of one of the series' biggest villains, giving a glimpse of how his life was molded to evil.

The True Backstory of My Hero Academia’s Villain Overhaul

Chisaki was in One of Dr. Garaki’s Facilities as a Child.

Close

Kai Chisaki, known by the villain name Overhaul, was taken in when he was a child in one of the many orphanages managed by Dr. Garaki. This was confirmed by a panel in chapter #419 of the manga that parallels one in chapter #158 when Overhaul was remembering his past. This revelation means that Chisaki was considered one of the “hatred seeds”, a test subject who could be manipulated into becoming All for One’s vessel in case anything happened to Shigaraki, just like Dabi, Nine from the movie My Hero Academia: Heroes Rising and Six from the Vigilantes spin off.

In chapter #151, it is implied that the Yakuza Boss picked Chisaki from the street and raised him. But before that happened, Chisaki had to forcibly escape from the orphanage. That would explain why he was covered in dirt and scratches when the Boss found him. AFO probably didn’t search for him because they already had a copy of his quirk and also because the kids in the orphanage were just “spares”. If Chisaki hadn't left, they probably would have turned him into an experimental villain, like those created in the factory in Vigilantes, or into a nomu.

The Experiments Overhaul Did Were Inspired by His Past

Chisaki's Origin Gives More Depth to His Obsession With Quirks

In the panel about Chisaki’s childhood in the orphanage, it is hinted that he was reading a book about the true nature of quirks, stating that it was a disease that came from mice and, most likely, that was what ignited his germophobia and obsession with quirk factors. But considering the things that Overhaul may have witnessed from Dr. Garaki and that he was a victim of experimentation himself, that surely developed his twisted personality and unethical behavior that led him to experiment on Eri and put his father figure, the Boss, in a coma.

Overhaul lost his quirk to Shigaraki (who ironically obtained his quirk from him), and after that, he didn’t show any remorse for his actions, only because he was no longer able to bring back the Boss. The guilt made Chisaki lose his sanity, but even then, he wasn’t interested in apologizing for the trauma he caused Eri. Overall, Chisaki is a completely irredeemable villain with a total lack of empathy, but his dark origin gives more depth to his mindset and makes him an even more interesting My Hero Academia character.