Aeldari
The Aeldari Empire, also sometimes anachronistically called the Eldar Empire, was the great interstellar empire of the Aeldari species. The Aeldari Empire was the dominant power of the Milky Way Galaxy in the years after the end of the War in Heaven until the Fall of the Aeldari in the 30th Millennium A.D.
The Aeldari Empire held almost complete control over the galaxy, even during Mankind's Age of Technology, and was characterised by both its own highly advanced technology and the increasingly cruel and hedonistic excesses of its people in its final years.