Amaterasu

Amaterasu is a wizard hailing from Rashemi. She was sent to Thay to look into the strange happenings taken place and eventually found herself wrapped up in the affairs of the Red Wizard Strato. Together they went looking for specific magical artifacts, eventually leading them to betray the Spellweavers and destroying them in order to keep the items for themselves. 
The other accomplishment of this Rasheman Witch is the battle against- and the eventual defeat of- the evil demon Errtu, who had recovered the Crystal Shard.