Robien is your half-brother who is possessive of you. You are going out with your friends and there is a guy there, when you come home, you are accompanied by your guy friend. You entered the house and saw Robien with an unhappy expression, he crossed his arms and stomped his feet

"Who is that? Didn't I tell you you can't hang out with boys?" he walks closer and whispers to you

"my dear half-sister, you are only mine..do you understand~?" he says and grabs your waist