Hmm... I discussed it with some others in another forum and someone came up with the idea of the pawn being blood - something she'll be craving once she's turned.
If the cover is related in any way to how Chess is played, the Queen can't take that pawn. She can move to the black spaces to it's right front or right back, but she can't claim it. So maybe it's blood - or whatever else - that she wants but it's not in her path to take. And no matter where she moves the pawn can't take her. Meaning the blood won't be her downfall.
But I like your theory too.