Donna Noble

Donna Noble was a fiercely independent companion of the Tenth Doctor. Despite humble origins, Donna Noble was noted by Rose Tyler as unknowingly being the most important woman in all of creation. (DW: Turn Left) While saving the universe, her mind was transformed into a Time Lord-Human metacrisis - the DoctorDonna. Unfortunately, her human biology was unable to cope with the increase in intellect, the sheer amount of knowledge and the Time Lord consciousness overwhelming her. The Doctor, to save her life, suppressed her memories of him so she no longer remembered either him or her travels in the TARDIS.