The Master (The Warrior's universe)

In the Warrior's universe, an incarnation of the Master that the Warrior was unfamiliar with appeared at his trial. The Master helped the Warrior seal the alternate timeline created by the Unified Skaroan Alliance in the Carrisent Particum. (AUDIO: Aftershocks)

Biography
The Master, a former enemy of "the Doctor that Was", fought in numerous battles during the Time War alongside the Warrior.

However, this timeline was drastically altered after the discovery of the Time Ring on Skaro, during the aftermath of the destruction of the Daleks by the Fourth Doctor. The Unified Skaroan Alliance then used this Time Ring to conquer Gallifrey, the Celestial Intervention Agency and time itself. After winning the Time War, the Alliance placed the Warrior on trial for the genocide of the Daleks. There, the Master was called to give evidence in the Warrior's defence. Unbeknowst to Narvin and the Alliance, the Master was there to help the Warrior seal this timeline within the Carrisent Particum, allowing it to never occur.

From this Particum, the Master was able to speak to the Warrior while he slept, moments after his regeneration. In these dreams, the Warrior would see flashes of this alternate timeline, and would hold conversations with the Master, where the Master would convince him to keep the Particum on his person. (AUDIO: Aftershocks)

Physical appearance
The Master appeared to be an elderly man with thin, grey hair. He was wearing what seemed to be a robe. (AUDIO: Aftershocks, AUDIO: Who Am I?, AUDIO: Time Killers)

Behind the scenes
Although he is played by Geoffrey Beevers, it is not made clear if this Master is intended to be an analogue to or some other incarnation. The Warrior claims he has not met him before, though he was also suffering from memory loss, and it is not clear if the incarnation that fought with him in the Time War before the trial was the same one.