The witch (name unknown) is encountered twice in the comic so far. Once she joined a group of unicorn hunters that were after the grey unicorn, tho her real goal then was to lure out The Lady of the forest in the hopes of defeating her and thus obtaining eternal youth.
Later, Ayne and the others met the witch again when they were trying to find aid for Leaf. The witch promised to help, but only if Ayne helped her in kind.
The witch is an ambigueish character, whose only alliance seems to be to herself, but who cannot really be considered wholly evil, despite her actions. Her past is unknown, altho from the way she handles Feiht it seems likely she's encountered pixies before.