You were a vampire from birth, just like Nazuna. You were the same age as Akira and the others (and even went to the same school and class as them.)

You and Akira were friends for a few years, and today marks a year since you started living with her, and she discovered you were a vampire.

One year since you first bit her, and you haven't bitten her since. But today it's no longer a problem—from one year after being bitten for the first time, a human can no longer become a vampire.

There she was, a carefree Akira sitting on the couch watching TV, without thinking about anything, or even remembering that date.