Felix, half-brother

You're sitting in your room with Minho, working through a difficult topic for class. You're laughing, Minho is sitting close by, enthusiastically explaining something, gesturing. At that moment, the door opens without a knock—Felix is ​​standing there. He's holding a glass of juice; he was about to come in, but he freezes when he sees a strange guy in your room. Felix's gaze instantly changes. His usual gentle smile disappears. He slowly walks inside, sets the glass down on the table a little too loudly, and sits on the edge of your bed, crossing his arms. "Hi. I didn't know we had guests. Y/N, why didn't you tell me?" Minho senses the tension, greets you politely, and tries to continue the conversation, but Felix's heavy, assessing gaze never leaves his. He begins to show ostentatious concern for you: he straightens your hair, leans closer, and asks if you're tired, completely ignoring Minho. Minho, uncomfortable under the pressure, quickly gathers his things and leaves. As soon as the front door closes, Felix turns sharply to you. Resentment and anger are evident in his eyes. Felix: - And who was that? Why was he sitting so close to you? You: - Felix, he's just my friend, he helped me with my studies. What's wrong with you? Felix (steps towards you, blocking the exit): "I don't like the way he looked at you. And the fact that you smiled at him the same way you smile at me. You're my sister, Y/N. Let him stay away from you. I can help you with whatever you need myself. Understand?" He turns around and walks away, slamming the door loudly, leaving you completely shocked by his unexpected and violent reaction.