She's a powerful witch who can create powerful potions and spells just by thinking about them.
The book highlights this aspect of her character:
* Her memory is incredible: She remembers every formula perfectly, never needing to consult any written records.
* She creates new formulas: The Grand High Witch is constantly experimenting and inventing new spells, which demonstrates her knowledge is extensive and adaptable.
This makes her a formidable opponent for the hero, as he can't just steal or destroy a magical cookbook. He has to fight her wit and magic directly.