Khan Noonien Singh
Khan Noonien Singh is an augment warlord from a twentieth-century Earth timeline in which he was ruler of one of the factions in the Eugenics Wars. When he was defeated, he stole the deep-sleep starship SS Botany Bay and escaped from Earth with a few of his people and was picked up 200 years later by the USS Enterprise.
Khan is a genetically-engineered "superman". He is approximately five times stronger than an ordinary human of similar size and build. He also has superhuman memory capabilities; these allowed him to memorize the technical specifications for the USS Enterprise in just a few hours. He does not appear to have significantly superhuman intelligence, although he certainly believes that he does.
Khan is a megalomaniac who craves power above all else. While competent in many fields, particularly leadership and strategy, he is overconfident to the point that he will assume his "superior intellect" is more than sufficient to compensate for his lack of experience in a particular activity (such as ship-to-ship combat in space). He is also extremely vengeful.