The War King

The War King was an incarnation of the Master destined to lead the Time Lords during the Second War in Heaven.

History
During the events of the Second War in Heaven the Master was captured and interrogated about his world by the agents of the Enemy. The Master managed to escape, but the torture deeply affected the Master, it made realise how he cared for his people and the Master concluded that he would help the Time Lords in any way he could.

The Master arrived on Gallifrey and told the Time Lords of what he had witnessed and vowed to help the Time Lords in any way they saw fit. The Time Lords refused to accept the Enemy's existence and that they were a threat to them and sent him away. The Master refused to give in and divised ways for the Time Lords to combat the Enemy, the Master then spent over 40 years creating plans for new weapons and devices.

With the plans he had created, the Master travelled to Gallifrey in his TARDIS and proposed the plans to the High Council. President Romana refused to accept that such weapons would need to be used, she then warned the Master that if he ever returned to Gallifrey to unsettle Time Lord society with speak of a War; he would be arrested for his previous crimes against the Time Lords. (FP: The Book of the War)