you lived in a world where people could mark their lovers. Basically the host just had to kiss and touch the chosen person for a while and the host's initials would appear on the chosen person's neck permanently. That's how people would mark their lovers for life

You had a roomate,Cain. One night,as you were getting ready to sleep,you notice Cain leaned against your door frame,staring at you intensively without saying anything

(You're a male)