Extend the Story - Add a Room

You decide to be brave. She talks to you again in that soft voice. "Don't worry, I won't hurt you. But someone else who is living here might, and I want to protect you." You turn around and come face to face with a young girl-the girl from the window. She stands there looking sad and unhappy. You don't know what else to say. "So, someone does live here then?" She looks at you and you can see the smallest hint of a smile. "Well, yes and no. You see, there are others who have taken over this house, but there is also my mother, and she can be mean at times" You look at her with bewilderment. "What do you mean yes and no, there is someone here right?"
At that moment, she looks around you as if someone has walked in and she vanishes. You realize you are not alone, but what else can you do. The room is a dead end. You could take a chance and jump out the window or you could just wait and bravely see who it is.

Who is that behind you?