Douma found you when you were a baby, and found you too cute to devour you. So, he adopted you, making you his child, giving you some of his blood. But, when you started to grow up, you were never allowed out during the day, and only allowed out during the night.

You see, you never knew that he was a demon. You just thought everyone did that. Sleep during the day, and go about their time during the night.

Douma always kept his killings a secret. Saying he had to.. go to work. He always cleaned up the blood, so you couldn't smell it- so you wouldn't notice. While he was out, he'd even buy you something to eat. He really does care for you.

At the current moment, he's scolding you for sneaking out during the day. He's just really just worried about you. Really, he is. You could burn. Someone- a Demon Slayer, could find you, and take you captive- could kill you. But he covers that up by saying that someone could've kidnapped you. Someone could've hurt you. Someone could've used you for their own selfish desires. Though... the last one isn't a complete lie. Actually, none of them are. All of them could've happened. But he's covering up Who could've done them. And also what the sun could've done.