Hydra is the conjectural label for one of Nine's stolen powers, a medium range Emitter Quirk that grows enormous shark headed serpents out of his back. He saves it for the people who think attacking him from behind is a good idea.
Nine never held this Quirk by birth. It came out of an unidentified Hero and passed to him through the theft that All For One as a Quirk makes possible, and the story never supplies an official name for it. Audiences meet the power in the film My Hero Academia: Heroes: Rising.
What emerges from the user's back are huge creatures somewhere between a snake and a shark, and they answer to his will completely. Their jaws are wide enough to close around a grown person and crush them.
Ordinarily Nine calls up a single serpent, though the thing divides into a pair once something strikes it. Dosed with an enhancer drug, he can raise several heads at once instead. Beyond ambushing anyone circling behind him, he can plant two of the creatures beneath himself and ride them upward into the air.

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Hydra is an unnamed Emitter Quirk that Nine stole from an unidentified Hero, letting him grow enormous shark headed serpents from his back that answer completely to his will and can crush a grown person in their jaws.
The villain Nine is the only known user of Hydra, a Quirk he acquired by stealing it from an unidentified Hero using his own power, All For One.
The Hydra Quirk debuts in the film My Hero Academia: Heroes: Rising, where Nine uses it in battle and catches Katsuki Bakugo off guard.
Nine normally summons a single serpent with the Hydra Quirk, though it splits into two once struck, and taking an enhancer drug lets him raise several heads at once.
Beyond ambushing enemies from behind, Nine can plant two of the Hydra Quirk's serpents beneath himself and ride them into the air.
Looking for more on Hydra? The My Hero Academia Wiki on Fandom has a dedicated page with community notes.
View on FandomThis content is original writing by Daddy Jim Headquarters based on the My Hero Academia anime series, manga, and official materials. My Hero Academia was created by Kohei Horikoshi, published by Shueisha, and animated by Bones. All rights to My Hero Academia and its characters belong to their respective owners. Episode and chapter references are cited where applicable.
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