my hero academiaThe Quirk-based combat system has grown and evolved significantly since the first episode, and not just in the variety of Quirks seen among capped professional heroes and the villains they fight. Quirks can be categorized in many ways, such as Emitter Types and Mutation Types, or even split between Support and Direct Assault Quirks.
A smaller, more informal Quirk category includes those that need extra fuel to operate. These Quirks consume an external, non-Alternate energy source to power themselves up, which sometimes has major implications for how the wielders of these Quirks fight or even how they view themselves. Five particular Quirks thus stand out among heroes, villains and innocent bystanders.
Momo Yaoyorozu’s creation quirk consumes lipids
Brilliant student heroine Momo Yaoyorozu has the remarkable Creation Quirk, allowing her to create inorganic objects from her bare skin. It might seem like a super-powered Quirk, but Momo doesn’t really create things out of thin air. Her Creation Quirk consumes her body’s lipids to power this Quirk, effectively transmuting the lipids into any item Momo wants to craft. This means that she can only produce a limited amount of material during a mission or battle, and overuse of creation makes her lean and frail. In the anime, Momo is usually seen eating a moderate amount of food, but during the Forest Boot Camp arc, Momo ate a huge amount of food to power up her Quirk and quickly craft many items. Momo needed to exercise her Quirk all day like a muscle, and that meant an endless stream of fresh calories to supply enough fat.
One For All is ultimately an energy storage oddity
At a glance, the unique One For All is a super-powered Quirk, and for the sake of secrecy, that’s what protagonist Izuku Midoriya suggested to his teacher Shota Aizawa at first. However, One For All is not muscle enhancement like Muscular’s Pump Up is. Instead, its true purpose is to store charged energy, and over the decades and over nine users, One For All has become heavily charged with powerful energy for Smash attacks.
Many years ago, a young All For One granted this Quirk to his little brother Yoichi Shigaraki to help strengthen the latter’s frail body. This, combined with Yoichi’s undiscovered Quirk, created One For All – an energy-based Quirk that can only be given to another person voluntarily. Now Izuku can perform devastating Smash and Shoot Style attacks with this charged energy, making him a multi-component Quirk. Neito Momona learned this when he copied One For All, only to run out of the stored energy needed to use it.
Eri’s rewind quirk needs its own power source
Young Eri carries a powerful Quirk mutation called Rewind. With it, she can reverse another person’s body to a previous state, potentially rewinding them to before they existed and thus erasing them from reality. Rewind’s full potential has yet to be explored, though Eri once used it to heal Izuku during the battle against Overhaul. More recently, Eri used Rewind to restore Mirio Togata’s Permeation Quirk in the my hero academia manga. Like One For All, Rewind needs a power source to function – a mysterious source that is obviously only found in Eri’s body. Neito Monoma copied Rewind, with the little horn, but lacked the power source to power it. For now, Rewind is Eri’s unique ability, and no one can copy or steal it for their own use.
Bloodcurdle & Transform Both require a target’s blood
Two villainous Quirks, Bloodcurdle and Transform, both require a horrifying fuel source to function: human blood. Bloodcurdle is Stain the Hero Slayer’s best weapon because once he ingests a target’s blood, he can willingly paralyze them for a few moments. On its own, Bloodcurdle is virtually harmless, but in practice Stain uses it to finish off helpless professional heroes with his swords and knives. Stain typically uses his katanas and tattered knives to slash heroes in ambush attacks to get those much-needed blood samples, then uses the same weapons to finish the job once Bloodcurdle activates.
Meanwhile, Himiko Toga, the evil trickster, needs blood to fuel his transformation Quirk. She can only assume a given person’s likeness when she has tasted at least one drop of their blood, and she can obtain blood samples with her knives or even the needles of her villain costume. Himiko obviously can only use it on human targets; there is no indication that she can feed her Quirk with animal blood to transform into a bird or a rat, for example.