Lsathranil's Shield is the name of an ancient device constructed by the Eldar race thousands of years ago. It appeared as an ancient arcane control panel which protruded from the stone on the ground itself and formed into a platform. Numerous dials were present which glowed with faint light and a series of switches blinked that were marked with runes to indicate the controls.
It was made by Farseer Lsathranil of Craftworld Ulthwé in order to contain the Necron forces that slumbered on the planet Rahe's Paradise with elements of its workings being present within the tablet known as Ishandruir. Remaining dormant for centuries, it projected a psychic field that imrpisoned the Yngir for centuries by making the sleeping Necrons believe that the Eldar were a dominant force in the galaxy. However, over the decades, the lack of maintenance on the machine led to it slowly breaking down over the decades. Ten millennia ago, the Eldar gave the world of Rahe's Paradise to a group of Humans in order to guard the sleeping tombs underground.
Farseer Macha of Craftworld Biel-tan recieved a vision that told her of the threat to the integrity on Lsathranil's Shield on Rahe's Paradise. This led her to summoning the military forces of her Craftworld and assembling them to combat the Human presence on that world. There, they combated the forces of the Imperium — in particular, they fought against the Blood Ravens Chapter who had been using Rahe's Paradise as a recruitment world for new Adeptus Astartes. This led to conflict with the forces defending the world and the continuing hostilities lead to the Yngir awakening slowly.
Ultimately, Macha and some of her colleagues went to the surface of Rahe's Paradise where they worked together with Gabriel Angelos as well as his soldiers to prevent the shield from shattering. However, the death of an Eldar vessel in orbit and the subsequent psychic death cry of its crew caused Lsathranil's Shield to break down and the Necron Lord on the world to awaken.
- 1: Dawn of War: Ascension — Blood Ravens: The Dawn of War Omnibus by C. S. Goto: