Tamasan was the pilot of Ollistra's Battle TARDIS.
She took Ollistra to get the Eighth Doctor on a jungle planet. She was a member of the Third Patrex Battalion. After Ollistra met with the Doctor, she arrested Bliss, Rupa Maguire, and Quarren Maguire. (AUDIO: Echoes of War)
She wanted to get the Celestial Intervention Agency involved in decontaminating the prisoners, but Ollistra didn't want to get them involved. She was in her fourth incarnation by the time she met the Doctor and had been fighting on the front line for 120 years. She was to be promoted if her next mission was successful and train the Doctor for war. She was the main trainer for his troop. When the Daleks attacked, she led the battle and told the Doctor where Bliss was. (AUDIO: The Conscript)
She later regenerated, was promoted to Major and met the Doctor and Bliss again. She travelled to Derilobia, and eventually ordered the evacuation of the planet when the Daleks attacked. She rescued the Eighth Doctor and Bliss with her TARDIS, while she sacrificed Carvil and his TARDIS. (AUDIO: The Lords of Terror)
After regenerating once more, she expressed a distrust towards Bliss to the Doctor over a call to his TARDIS. (AUDIO: State of Bliss) The Doctor later contacted her to ask that their armies steer clear of the Seas of Nemacene, having made a promise to protect the trade routes there and save planet like Iptheus from total starvation. Tamasan updated the Doctor on a recent victory over the Daleks, and refused to offer such a protection. After informing him of the Dalek Time Strategist's newest plans, which were threatening the multiverse, Tamasan was called away to the Panopticon. (AUDIO: The Famished Lands)