Sontar (The Infinity Doctors)

General Sontar was the Imperator of the Sontaran Empire. He was said to look older than other Sontarans and was important enough to share the name of his people's home planet Sontar. (PDA: The Infinity Doctors)

He masterminded the two thousand year war against the Isari.

Possibly Apocryphal Information
There is an account of a Sontaran known as Sontar trapped in an Egyptian Pyramid; it is unclear if this is the Sontar or another individual known by that name. (DWM: The Gods Walk Among Us)

Behind the scenes

 * The suggestion that the Sontarans derive their name from a single person originated from the FASA Doctor Who Role Playing Game which claims that they named their planet after him.