Rewind

Rewind (人を巻き戻す) is a Quirk used by Eri. It is the result of an extremely rare mutation, and bears no resemblance to any Quirk on either side of her family's lineage.

Description
Rewind allows Eri the ability to bring an individual's body to a previous state.

When her Quirk is activated, Eri's horn glows brightly. Those that are in contact or near Eri at the moment of the activation start having their bodies rewound to previous states, undoing or bringing back injuries or modifications from the present or the past. She is capable of reverting people back to a point before they even existed, effectively killing them. Kai Chisaki implies that, with enough mastery, Eri could even de-evolve humanity back into a primal state. It was also suggested by Shota Aizawa that her Quirk can even rewind the bodies of those who have lost their Quirks and restore them. Shota Aizawa wanted Eri to master her powers enough for her to restore Mirio Togata's Quirk.

Through several tests and experiments, Shie Hassaikai was able to utilize the effects of this Quirk to target a person's "Quirk Factor," in order to create Quirk-destroying bullets.

Because of her young age and inexperience, as well as lack of information, Eri is unable to properly control her ability, being able to activate it but unable to stop it. So far, the only known methods to stop Rewind is through Chisaki's disassembling ability and Eraserhead's Erasure ability.