The War Chief

The War Chief was a renegade Time Lord who assisted a group of aliens known as the War Lords in the 1969 serial The War Games by Malcolm Hulke and Terrance Dicks, which was the last to feature the Second Doctor.

The War Lords had been kidnapping soldiers from various wars in Earth's history to play war games on an unknown planet. The War Chief provided the War Lords with basic TARDIS-like travel machines, which they used to kidnap the human soldiers and travel between era-specific zones they had created.

When the War Chief and the Doctor came face to face, they recognised each other. The War Chief wanted the Doctor's help to double-cross the War Lords and seize power for himself. The Doctor immediately refused, and instead reluctantly summoned the Time Lords for help. The War Lords found out the War Chief's plans to betray them, and executed him.

Although the War Chief was shot and apparently killed at the end of The War Games, some fans choose to believe that The Master (the Doctor's arch-enemy, introduced in Terror of the Autons a couple of years later) is the War Chief in a new guise, due to similarities between their appearances and modi operandi and the fact that the War Chief's body is removed immediately and not seen thereafter.

The spin-off novels, however, include a novel featuring the return of the War Chief (Timewyrm: Exodus by Terrance Dicks), a novel featuring the Master set before The War Games (The Dark Path by David A. McIntee), and a novel featuring younger versions of both characters (Divided Loyalties by Gary Russell) establishing that the two are not the same person, at least in the continuity of the novels, which are themselves of uncertain canonicity when it comes to the television series.