WARNING: The following contains spoilers for My Hero Academia #312, by Kohei Horikoshi, Caleb Cook and John Hunt, available now in English from Viz Media.
My Hero Academia is currently having Deku brave the streets of a villain-ravaged Japan alone -- in a desperate plan to bait out All For One -- and in that time, he's run across all manner of roaming villains. He defeated Muscular with the help of the Ketsubutsu hero student Yo Shindo and fended off a violent mob from an innocent woman with a mutation Quirk. However, a new villain has entered the scene in the manga, and she has a good shot at being too dangerous for him to handle.
Known as Lady Nagant, this villain is a traitorous ex-hero who was imprisoned in the supermax prison Tartarus before All For One destroyed it. She's considered the best sniper in Japan, with a three-kilometer range, surpassing even the pro-hero Snipe, whose Quirk enhances his accuracy. Snipe has admitted he can't compete with her because she outclasses his Quirk with raw skill alone, even before her Quirk -- called Rifle -- is factored in.
We don't yet know for sure everything Lady Nagant can do with her Quirk, but at its base, it allows her to turn her arm into a rifle and create custom bullets out of her hair. She can shape her hair into all kinds of ammunition, including hollow point and curving ones, and their blue-and-pink color is an instant warning to Deku that he's facing her after he barely managed to dodge a shot using his Danger Sense. Lady Nagant is the one villain that Hawks warned him to drop everything and run from, and the #2 hero isn't even aware of the new weapon Lady Nagant has in her arsenal.
In a flashback from Lady Nagant's perspective, we learn that All For One has recruited her to capture Deku, and in exchange for this, he gifted her a second Quirk: Air Walk. With a new and unexpected method to set up long-range shots on her enemies, she's likely more deadly than she's ever been. So, with two Quirks, a mysterious past involving her killing a fellow pro-hero and a commitment to obliterating hero society, she's no ordinary opponent for Deku.
This is both a welcome and long-overdue change given My Hero Academia's previous track record with female villains. Of the dozens and dozens of villains the series has featured, only three of them were women before Lady Nagant's introduction. Of these three villains -- Himiko Toga, Magne and Curious -- the latter was killed almost immediately after she first appeared to further Himiko's character development. Plus, Himiko herself has never been considered a major force on the battlefield. Lady Nagant is the first truly powerful female villain we've seen.
Given this, hopefully, she has an impressive impact on the series, similar to the pro-hero Mirko's moment in the War Arc. It would be a shame if Deku soon defeats her without too much trouble.