Alec Trevelyan/Bio & Battles

Once known as Agent 006 under the employment of Her Majesty's Secret Service, Trevelyan betrays MI6 during a mission to blow up the Arkhangelsk chemical weapons facility in the Soviet Union while working with his close friend, James Bond.

During the operation, Trevelyan is caught and apparently executed by the base's commander, Colonel Arkady Ourumov. Presuming Trevelyan dead, Bond continues the mission and escapes aboard a supply plane. Nine years later, Bond's pursuit of a stolen helicopter and investigation of an explosion at Severnaya leads him to Saint Petersburg, where he learns from Valentin Zukovsky that "Janus", the head of the crime syndicate responsible for the theft, is a Lienz Cossack. Later, when he finally meets Janus, Bond is shocked to discover Trevelyan, who staged his execution at Archangelsk and now employs Ourumov, now a General in The Russian Army. Trevelyan's face is scarred from the explosion at the weapons factory, a direct result of Bond changing the sequence detonation timers.

Trevelyan reveals that his motive for his betrayal is a personal one. His parents were Lienz Cossacks who had collaborated with the Nazis but attempted to defect to the British at the end of World War II. When The British instead sent them back to the USSR, many were executed by Stalin's execution squads. Though Alec's parents survived, his father, ashamed to have lived, killed his wife and himself. At the time, Alec was only six years old.

He was then transported to the United Kingdom, and was taken in by MI6, who issued him the new surname Trevelyan, chosen because it had origins in the British Isles, but bore coincidental phonetic similarities to Armenian and other southeastern European surnames. MI6 continued to sponsor his training and education throughout his childhood, and he began formal work for the British government upon attaining his majority, in order to set revenge against the British government for his family's demise.

Source: Alec Trevelyan on Wikipedia