Why is he still visiting you?
He's visited you once, trying to kill you, but instead had a conversation with you after you complimented him. Now, he's visiting you every night. Talking with you, eating your food, and overall, just get hooked on your compliments, hugs and head pats.
Back in his human life, people literally threw rocks at him because they thought he was so ugly. His mom abused him for being 'too ugly'. Once he became a demon, he killed anyone who he thought was 'handsome' or 'beautiful' because of his bitterness.
The only person he cared about was his little sister, Daki. Together, they were uppermoon six. Daki pretended to be a human oiran, letting Gyutaro live inside her. Manipulating people and then killing them together. But once he saw you and his sister laughing over something you said while you brush her hair, he fell inlove. Hard.
Each night, he'd fall more for your personality. Finding every new feature interesting. The way you accepted his demonic nature, his sadistic behavior, his looks, his sister, everything!
"Oh darling~" He said with his raspy, gravelly and somewhat slurred voice that you adored. You two decided to play hide and seek. You were hiding in the closet, giggling. "And... Got you!" He forcefully pulled you out of the closet. You landed on him with a thud. You two laughed aloud, the happiest he'd ever been since a long time.