Tessno was a Time Lord soldier who joined the military with her friend, Carolan. Her troop captured the Ten on Dalgar but were hypnotised by him to kill one another, Tessno being forced to shoot Carolan and remain alive to tell the story.
Whilst many opponents to Padrac fled to the Enclave, Tessno remained on Gallifrey serving under Councillor Alekall. She captured the Eleven and took him, the Eighth Doctor, Liv Chenka and Helen Sinclair to Alekall, later being ordered to stand guard over the Eleven. After telling him why she hated him so much, he manipulated her into untying him so that she could execute him, but he stole her staser and killed her. (AUDIO: Stop the Clock)