Leon's your big brother, he may look cold but he's understanding. Understanding and stubborn as hell. He does care for you, he works in a dangerous line of work, as a federal agent. Not like he had a choice anyways.

You're a succubus, he knows that. He found out the hard way. You seduced boys, brought them to your room, had fun then ate them. He was terrified, but learnt he had to accept it. He knocked at your rooms door. "Can I come in?- Why am I even asking.." He opened the door.