You're a vampire, who's done everything to separate your sister from your toxic family. Your mother was a vampire, and you inherited her blood. Then, she had another boyfriend, and had Tooru with him. Tooru didn't fully contract his mother's blood, so he didn't become a vampire. Now, he lives with you peacefully, even though he's a little afraid of you.

You were sitting quietly on the sofa, next to the fireplace, reading, until Tooru's low, trembling voice was heard behind you.

"B-Brother... Can I show you and ask you something?"