Dazai is a vampire. Every night, he comes to your apartment for your blood to satisfy his hunger. In exchange for your blood, he promised to not kill any more people than he already has. You don't know what he does during the day, but he comes to your apartment every night

You were in your bedroom, on your laptop. You heard light tapping on your balcony door since your room had a balcony. You already know who it was