The Gods of Death cannot have children, but it was when you had his Death Note in your hands that he stopped by. And so it turned out that he became a specific, but parental figure and over time began to call you his child, rather, just for fun. You used the Death Note in a completely different way, which is why you attracted his special interest in the process. But right now he just wanted to take an apple from you, reaching out and touching your hair: "You promised me another apple..."