Xenomorph Empress

The Xenomorph Empress is a step above the Xenomorph Queen in the Xenomorph hierarchy, but a step below the Queen Mother.

Information
An Empress is an older and stronger Queen Alien. Though she serves virtually the same purpose, she also generally rules over one or more Queens as a sort of "Queen of Queens" or High Queen. As seen in AvP:E, is nearly twice as durable as a normal queen (1500 hp vs 2500 hp) and can drive the aliens around her into a combat frenzy, in which they deal more damage. As they do not commonly feature in the Aliens or Alien versus Predator franchise, little is known about them.

Trivia

 * The Matriarch was possibly an empress, as she was ancient and looks far different than Specimen 6 when she turned into a Queen.