Human (Attack of the Graske)

A young, unidentified human (PROSE: Companions and Allies) aided the Tenth Doctor in defeating a Graske. (GAME: Attack of the Graske)

Biography
After leaving Rose Tyler in 1979, the Tenth Doctor picked up the human in his TARDIS, having them identify a Graske who was posing as a mother. The Graske, once identified, fled.

The human piloted the TARDIS upon the Doctor's instructions, tracking the Graske down to London, 1883. After the human located the Graske, it fled once again, this time to its home planet, Griffoth.

On Griffoth, after solving a number of puzzles, the human and the Doctor then made their way to a chamber filled with the humans that the Graske had snatched in order to assume their places on Earth. The human was then posed with a choice, either to free the captives or to leave them. The individual then decided, with the Doctor sharing his thoughts about the human's choice. The Doctor returned the human home, with his opinion on the human varying based upon their decision. The Doctor then departed, wishing the human farewell. (GAME: Attack of the Graske, PROSE: Companions and Allies)

Behind the scenes
The "human", the main character of Attack of the Graske, is a blank slate of sorts to accommodate the player to fulfil the role of the character, like an avatar, thus meaning that what one random individual's personality or appearance is irrelevant. Moreover, Companions and Allies treats the unidentified human as a proper character, devoting an entire page to them.