In an alternate universe, 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. He masterminded the two thousand year war against the Isari.
When Sontar visited Gallifrey, the Doctor showed him around the Capitol. Sontar observed that the Citadel was designed as a fortress; this surprised the Doctor, who had never realised it before but found the observation obvious in hindsight. (PROSE: The Infinity Doctors)
Legends told that he was killed by the Rutan Queen at the beginning of the war with the Rutan Host. Before he died he was the founder of the Grand Strategic Council and after his death they took his place as the leaders of the Sontaran Empire. His DNA was used as the master template of every Sontaran cloning tank. (PROSE: Lords of the Storm)
On Gallifrey Eight, Lord President told Homunculette about when the old general of some aliens came to Gallifrey long before the War. One of the President's friends showed the general around the Capitol, and the general observed that it had been built for war. Then, the President and his friend had never imagined that the Time Lords would ever start designing and breeding efficient killers like the general did. (PROSE: The Taking of Planet 5)