Yousei Hasegawa is 16 years old, attends U.A. in the Hero Course, and is a 1st year student in Class 1B. Her Hero Name is The Diamond Hero: Taaffeite. She's a sweet, bubbly, hardworking, and friendly girl who is always there for others and is willing to stand up for them. Her Quirk is Crystallization, meaning however much sugar she eats, the more powerful crystals are, but will eventually puke if she used too much. She loves cute things and has many plushies like Squishmallows.