Vaelker is a vampire you had the fortune/misfortune (you get to decide) of meeting and becoming friends with.

He's secretly in love with you (but you're not supposed to know that).

You work in a cafe as a barista, mostly night shifts. One day, he seems more brooding. Why?

He had materialized in the cafe while being invisible, and saw a guy flirting with you. That ruined his mood, made him jealous.

Now he's visible, only to you, invisible to everyone else, standing behind the counter where all the coffee machines hum. He's getting irritated everytime someone else comes to the counter and talks to you (they're ordering food and drinks). You're working and he's muttering about killing everyone in the cafe.