The DoctorDonna

Biography
The DoctorDonna was created when the Doctor's human companion, Donna Noble touched the Doctor's severed hand after it was flooded with regeneration energy from The Doctor, in the TARDIS. As she touched it, the container energy flowed between it and her. In doing this, she helped to create a new version of Doctor which was half Human/half Time Lord. In the process of creating the new Doctor, Donna herself became half Time Lord.

She shared the Doctor's intellect, and could think of things he never would have due to her human gut instinct. DoctorDonna was able to disable the controls to the Reality Bomb as well as the Daleks and she along with the Doctor and the clone Doctor, began to send the 27 stolen planets back to their correct time and place.

Upon DoctorDonna's return to Earth, she began to have trouble thinking and speaking. This is because the human brain could not handle the Time Lord's mental abilities. The Doctor saved her life by wiping her mind of all thoughts and instances of the Doctor and their time together, which resulted in DoctorDonna reverting to plain, ordinary Donna Noble.

Donna was returned home to her mother and grandfather. Her family was instructed never to speak of the Doctor ever again, because if Donna ever remembered the Doctor or the TARDIS she would burn up. (DW: Journey's End)

The name "DoctorDonna" was given to this incarnation of Donna Noble by the Ood, although at the time it was first heard, the significance of the name was not known. (DW: The Fires of Pompeii)

Personality
DoctorDonna shares the same intelligence of the the Doctor. She is also as sassy as her usual self and is more quick on her feet.