Yui Kodai (小こ大だい唯ゆい, Kodai Yui?), also known as Rule (ルール, Rūru?), is a student in Class 1-B at U.A. High School, training to become a Pro Hero. Quirk: Size (サイズ, Saizu) Yui's Quirk grants her the ability to alter the size of any nonliving object that she touches. She can return objects to their original size by pressing her fingertips together.