Emperor of the Terran Empire

The Terran Empire of the Mirror Universe was led by an Emperor or Empress that served as the head of state and possessed near absolute power of the empire. This positions origin come from the Terrans of the Mirror Earth who formed an interstellar empire based on conquest.

The earliest known Terran Emperor was during the 22nd century when the conquered races were rising up against the Emperor forming a rebellion that the Terran Empire was hardpressed to contain. Eventually, this rebellion was destroyed when the mirror universe version of Jonathan Archer managed to procure the USS Defiant and used it against known rebel forces. However, he was poisoned and the ship, perhaps the most advanced starship within that time period, fell into the hands of Hoshi Sato who took the vessel to Earth and declared herself Empress of the Terran Empire by overthrowing the ruling Emperor. It is not known what her reign was like.

(ENT episode: In a Mirror, Darkly, Part II)

The mirror universe version of James T. Kirk aspired to reach this position (Startrek TOS: "Mirror, Mirror") and infact succeeded. However, he was betrayed by his Prime Minister the mirror universe version of Spock. Once this was done, the position of Emperor was left vacant and the imperialistic Terran Empire collapsed. Despite this, the mirror Kirk kept the title, even though the Empire was conquered by the Klingon-Cardassian Alliance.

(Star Trek Novels: Spectre and Dark Victory)