The War Chief

The War Chief was a renegade Time Lord of the High Council who assisted the War Lords.

Post-regeneration
The War Lord encountered his future War Chief in a Trastevarian jail, where he was so close to death that he regenerated. He told the War Lord that the Sisterhood of Karn's Elixir of Life was vital to his people's regeneration process. (PROSE: Save Yourself)

Ally of the War Lords
Now calling himself "the War Chief", he worked with the War Lords. They abducted soldiers from wars spread across Earth's history, though they didn't go too far because of the risk of humans' technological knowledge, for simulated versions of the wars from which they came. Thinking humans the most vicious species in the galaxy, the aliens hoped to pit the survivors against each other and use them to conquer Mutter's Spiral once they had eliminated the weak and the cowards and were left with the hardier warriors.

The War Chief aided the War Lords by helping them build SIDRATs, TARDIS-like space-time machines. They used them to kidnap the human soldiers and travel between era-specific zones which they had created. The War Chief and the Second Doctor met and recognised each other, with the War Chief acknowledging the Doctor's change in appearance. The War Chief solicited the Doctor's help to double-cross the War Lords and seize power for themselves. The Doctor pretended to accept the War Chief's offer.

The Security Chief of the operation distrusted the War Chief, believing he meant to call in the Time Lords. While the Security Chief was willing to accept the War Chief had upheld his part of the bargain and had been afforded every need, he had still refused to tell them how to construct the SIDRATS.

The two engaged in a series of machinations against each other which ended with the War Chief disgraced when the Security Chief recorded a condemning conversation between the War Chief and the Doctor, and he took it to his leader. The War Chief got his revenge when he shot his rival dead. Unable to resolve matters, nor return the soldiers to their own times, the Doctor summoned the Time Lords for aid, while the War Lords uncovered the War Chief's plans and executed him, though he tried to talk his way around it, claiming those plans had been faked, but he wasn't believed. (TV: The War Games)

Unknown at the time, while the War Chief remained on the War Lords' ship, the War Chief did not die but, rather, underwent a faulty regeneration. His new form looked like two bodies fused together. He took to wearing cloaks, hoods and cane sticks to disguise the fact, with white hair and a bushy white beard, eventually convincing the War Lords that his 'betrayal' of them was just a misunderstanding. (PROSE: Timewyrm: Exodus)

Personality
The War Chief was an ambitious and arrogant individual, cunning, and with great tactical abilities. He pretended to serve the War Lords loyally, while plotting to take control of them after they succeeded in their plans. He also made feuds easily which made it easy for his allies to turn against him. (TV: The War Games)

Behind the scenes

 * The necklace prop the War Chief wears in The War Games is the same prop previously worn by Zephon in The Daleks' Master Plan.
 * In 2023, a fan-made infographic of the Master's incarnations which identified the War Chief as the "Eleventh Master", immediately preceding Roger Delgado's, was retweeted by the official Big Finish Productions Twitter account, who compared the character profiles to "new Weetabix cards". The artist replied to the retweet, half-jokingly pointing out the apparent acknowledgment of "the truth of the Eleventh Master".