The White Stag

I was protected by the monsters under my bed when I was a kid in the foster system. I have a feeling I could use them again.
My time in the foster system wasn't great. Maybe they were imaginary, but when things got bad, the boogeyman and an imp always came to my aid. If I needed to run, a beautiful white stag would appear at my window to let me know to get out of there. I've touched the stag. I know he's real.
Alastair Rex saved me from the streets and another bad foster home. He's never raised a hand to me or tried anything inappropriate. But I'm a doll in his playhouse. I can only leave when he lets me. I dress in the clothes he wants me to wear. I say what he wants me to say because I get the feeling he would react violently. I could use my monsters, but they disappeared the day Alastair showed up in my life.
Until I look out of my cage and see the white stag again. It's time for me to escape Alastair Rex.