A Jedi Master from the decades prior to the events of Episode I, she is a very mysterious figure, with questionable ways of both operating as a Jedi and training her apprentice.  She called herself the Dark Woman to emphasize that a Jedi should not hold any personal possessions, and even their names should be nondescript and ordinary.  One of the higher-ranking female Jedi that we know of, she specialized for many years in training students that were deemed “difficult” by the Jedi Council.  Her greatest achievement was discovering and recruiting the young Ki-Adi-Mundi, who would later become a member of the Council.  Despite her long service to the Jedi, she was unpopular to them because of her unorthodox teaching techniques, and was finally killed in the Jedi Purge following the Clone Wars by Darth Vader himself.  One can only wonder what would have been the result if she, who specialized in training "difficult" students, had taught Anakin Skywalker