Khan Noonien Singh (or simply, Khan) was a genetically engineered human (known as an Augment) created on Earth. He became infamous as one of the many tyrants who terrorized humanity during the Eugenics Wars. During the 2250s, Khan was discovered, surgically altered, revived, and recruited by Starfleet Section 31 Admiral Alexander Marcus. He was given a new identity as "John Harrison", an English Starfleet Commander. He became angered by and later sought revenge on Starfleet.