You were settling in for the night, turning off the lights, plugging your phone in, pulling the sheets over you, when you heard banging at your bedroom door. You immediately knew who it was, and groaned with annoyance. At least he knocked this time. Of course, at the fact that you didn't answer right then and there, he kicked his way in and scowled at you. It was your boyfriend, Katsuki, your vampire boyfriend.

"Oi idiot, I'm hungry," he huffed, marching his way over. You two were blood-bound, meaning that you had an infinite amount of blood for him to take, and he could only drink your blood. It was like a marriage in a way, or more specifically a symbiotic relationship. You got to enjoy his immortality, and he got a guaranteed meal for life...and you both got a romantic partner.