5 Best Anime Series Where the Hero Is Cursed to Become a Monster

Some of anime’s most compelling protagonists aren’t fighting monsters from the outside; they’re fighting the one growing inside them. These stories are about power with a price: a curse, a fusion, a bloodline, or a bite that slowly turns the protagonist into the very thing they’re supposed to defeat.

Their internal conflict has produced some of the genre’s most emotionally rich storytelling, turning ordinary shonen power-ups into genuine tragedies. Some anime lean a lot into this “cursed to become a monster” premise, each handling the transformation in its own unforgettable way.

1 Solo Leveling – Jinwoo Is a Vessel for the Shadow Monarch

Sung Jinwoo from Solo Leveling starts out as the weakest hunter alive, but a mysterious system turns him into a vessel for the Shadow Monarch, an ancient and terrifying entity capable of killing godly beings. As his power grows, he gets closer to the turning point of losing his humanity entirely. Every level-up pulls him further from the ordinary man he once was, a change that is visible in his own behaviour.

Where to Watch: Crunchyroll

2 Tokyo Ghoul – Kaneki Turns Into a Man-Eating Monster

In Tokyo Ghoul, Ken Kaneki’s life is shattered after an emergency organ transplant leaves him half-ghoul, craving human flesh he’s horrified to want. This anime turns this transformation into a slow psychological unraveling, as Kaneki is rejected by both humans and ghouls alike. His curse is the erosion of his identity, as he doesn’t just want that human flesh; he is more than capable of taking out anyone and eating them, so he constantly has to hold himself back.

Where to Watch: Crunchyroll

3 Jujutsu Kaisen – Yuji Is Destined to Become a Monster Before Dying

In Jujutsu Kaisen, Yuji Itadori swallows a cursed finger, unknowingly making himself the vessel for Sukuna, one of the most powerful and monstrous sorcerers in existence. From that moment, Yuji is living on borrowed time, aware that his body could become a weapon for destruction the instant Sukuna seizes control. He is already sentenced to death, but the plan is to kill him after he has consumed all of the fingers. However, it was clear in Shibuya that he is losing more and more control of his body as he eats more fingers.

Where to Watch: Crunchyroll

4 Attack on Titan – Eren Becomes Everything He Hated

Eren Yeager grows up despising the Titans that destroyed his home and killed his mother, only to discover he can transform into one himself. Attack on Titan uses this irony brutally: the boy who swore revenge on monsters becomes indistinguishable from them, both in power and, eventually, in ideology as well. This is what makes him one of the best protagonists who actually turned into a villain.

Furthermore, we later find out that this curse was given to him by himself from the future, as he is the one who manipulated his father’s actions. This was one of the most masterfully written plot twists about a character. His curse forces him to wield the very thing he once feared, and as the anime progresses, the line between “hero” and “villain” blurs until it nearly disappears.

Where to Watch: Crunchyroll

5 Chainsaw Man – Denji Fuses With Pochita, Becoming a Monster Himself

Denji’s fusion with Pochita gives him the ability to transform into the Chainsaw Man, a violent, blade-wielding monster capable of shredding devils apart. Unlike other heroes on this list, in Chainsaw Man, Denji doesn’t fear his monstrous side so much as he learns to wear it. This anime turns the curse into dark comedy and brutal spectacle, without ever losing sight of the humanity Denji is desperately trying to hold onto.

Where to Watch: Crunchyroll

Which of these anime do you think handled the trope perfectly? Let us know in the comments.