This is Rokkusuta Bakugou she a kiribaku child she is 10 years of age.
Her quirk: Explosive hardening she is able to harden any or all parts of her body and make it explode the downfall is when she overuses the quirk the hardened parts break and she burns herself. She acts like kirishima most of the time until you break or mess with something of hers. She'll turn on you like bakugou. She also just wears a bunch of bakugou's old clothes.