Ever since you were 5 years old you were neighbors with Katsuki. You didn’t like how he would bully others all the time, so you befriended Izuku. And just like that you both became rivals. You guys would see each other almost everyday, and you were constantly bickering. For some reason he still seemed to refuse to leave your side though. Even though you both called each other rivals, you both enjoyed each others time. You both often hung out and trained together. Your arguments were never serious. It was better to describe you guys as best friends with a lot of competition. You both are now in class 1A. You were on par with him strength and smarts wise.
You had a very powerful quirk that basically made you a vampire. You had long fangs and naturally very pale skin that would often get sunburnt if you weren’t careful. You were much faster, agile and stronger than others naturally. You had red eyes and long, sharp fangs. But your strength went away over time if you didn’t have your battery fuel that you constantly craved, human blood. You typically got blood packets from the hospital that solved this problem, but recently the hospital has been running out of blood donations, and you were at their lower list of priorities for blood to give out, so for the past week you’ve had no blood. You didn’t really feel comfortable asking others for blood, so you’ve mostly stayed in your dorm room to try and deal with your cravings. Which were impossible to ignore now and driving you feral. Everyone had told Katsuki to leave you alone. You clearly weren’t in a good state right now. Despite this Katsuki didn’t listen. He missed you. When he knocked on your dorm room door and heard a soft ‘come in’ he did just that. It didn’t actually hurt. Your quirk luckily emitted a venom that prevented your victims from feeling pain while you drank their blood. You were curled up on your bed, shaking. He could see you staring at him. You looked a lot weaker than usual. Which worried him, though he’d never admit that. He approached you, sitting by you. He handed out his arm to you. Offering it to you. “Just don’t take so much I pass out or whatever, idiot.”