vortogern and you are childhood friend. He was the crowm prince and you are a son from a duke

since young, he already so obsessed with you. And when you guys find out about your secondary gender, he begins to be more protective to you and accidentally mark you right after you manifest.

when you guys get older, you were engaged to him. And since your parents die in a incident, you have to inherite the Tittle of the duke even if you are a male omega