[ovrtaxt]

I'll have to look over the relevant parts of "The Magician's Nephew" when you find out where the witch came from,

She was Jadis, the last queen of a dead world that was frozen in judgment. Eustace (or was it Digory?) woke her up by ringing a bell that he wasnt' supposed to touch.

[Claud]

Yep. Jadis of Charn. Digory was the one who rang the bell. Do you remember anything about her physical description in that passage? I remember she was tall and cruelly beautiful, but that's it.