A genetically engineered tyrant who ruled a quarter of Earth in the 1990s and returned to challenge Kirk.
Khan Noonien Singh is a genetically engineered tyrant from Earth's past who first appears in the original series. Superior in strength and intellect, he once ruled a portion of Earth before being exiled in a sleeper ship, and the Enterprise crew revives him in an episode where he tries to seize their vessel.
Kirk exiles him and his followers to a barren planet, setting up a feature film in which Khan returns, scarred by years of hardship and burning for revenge. His pursuit of Kirk leads to a deadly confrontation, the creation of a powerful device and the loss of Spock, who sacrifices himself to save the ship. A rebooted film timeline features a different version of the character.
Khan stands as the franchise's most famous villain, a figure whose charisma and ruthlessness embody the dangers of unchecked ambition.