The Master

The Master is a renegade Time Lord. They were a former childhood friend of the Doctor, now bitter rivals.

History

 * The Master's history prior to their appearance in The Game of Rassilon can be found on the TARDIS Data Core.

Prior Adventures
The Master had previously attempted to overthrow the government of a planet in an act of conquest, only to find the Slitheen had beaten him to it. He worked with the Previous Doctor to try and stop them. This was the last time the Doctor saw him before their encounter on Nark.

Susan and the village on Nark
When the Doctor arrived on Nark, he met the Master again - she found he had no memory of his previous identity and had instead taken up the mantle of "the Protector" - he was protecting a village of diminutive humanoid aliens, but also protecting Susan, a young woman he believed to be his granddaughter - Susan explained that they were traveling to their home planet of Zeta IV when the ship crashed on Nark, stranding them.

The Master had erected an electric dome around a village occupied by the aliens, but the arrival of the Doctor's TARDIS, which bisected the field, shorted it out. The Doctor and Travis assist with repairs, but the village is attacked by the Time Lords.

Upon seeing the Doctor's TARDIS, the Master's memory was restored. With the Time Lords approaching, he faced an inner conflict between wanting to help the villagers and Susan or wanting to kill everyone. Ultimately, Susan made the choice for him, sending him into the woods with his TARDIS, but not before he activated some traps and killed a significant number of the Time Lord group troops.

Inside his TARDIS, the Master looked at his display and saw on the screen the body of one of the villagers he had befriended. He felt that if the villager were alive, he would have returned to the village. Instead, he decided it was time for him to leave and kill something else, and he departed.

The Universal Backlot Fire
The Master, posing as the Preservation Commission, intercepted the Doctor, Travis and Carrie as they were making their return from the Land of Fiction and tasked them with collecting three historical items destined to be lost in the 2008 Universal Studios backlot fire. However, the Doctor discovered something was amiss and the Master revealed himself, vowing revenge for the Doctor destroying his old life on Nark.

Appearance
This Master carried a cane, which he also used as an offensive weapon.

Behind the Scenes

 * The Master was played by voice actor Dino Andrade. Dino has a number of villainous roles under his belt, including the Scarecrow in Batman: Arkham Asylum and Professor Putricide in World of WarCraft.