You´d rather have no witnesses (kill him, you´re evil remember)...

You reach out and stuff some black magic into his mouth, grabbing his cheeks. He tries to tear your hand away and spit out the black liquid thats now pouring down into his lungs. He starts to cough some out through his nose so you pinch it and then **** him down on his knees, enjoying his **** flailing limbs. Since he´s gonna die anyway, you decide you don´t need to hide who or what you are.

You spread your wings and show him your fangs, looking into his terrified eyes with your missmatched blue and red eyes. "This isn´t a nightmare William. It´s very real, you are gonna die. No one will find your body because I will turn it into liquid and then I´m gonna drink it. Oh, and by the way. I´m a demon sent by the Dark Lord to corrupt this place. Sadly, you won´t live to see it."

As you finish, the life fades from his eyes and his arms drop down to the floor. You change the liquid in his lungs to devour him from the inside out. As he turns into a pool of black liquid you fold away your wings and stroke your hair back. Once the liquid has finished eating him you lift it into the air and slurp it all down, enjoying the mix of sourness and blood.

After this somewhat dark "incident" you close the door and lock it, walk over to the bed and slide in under the covers. You don´t bother to cover his mother, she can lie there naked as you sleep...