Eidolon is a Daemon World, originally part of the ancient Eldar empire. This former Maiden World was hidden deep within the heart of the Eye of Terror. During the Fall of the Eldar it was enveloped by the Warp explosion instigated by the birth of Slaanesh and Warp energy has twisted it beyond all recognition. Like the state of Chaos itself, the land mass of the Daemon World is in a constant state of flux and is divided into four separate empires, each one claimed by one of the Chaos Gods and ruled by a Daemon Prince. Each of these realms wage eternal wars against one another. Eidolon is also supposedly home to many valuable ancient Eldar artefacts dating back to the time of the Fall. Eidolon was the site of fighting during the massive incursion of the Forces of Chaos into Imperial space during the 13th Black Crusade in 999.M41.
- Bloodquest (Graphic Novel Series)
- Eye of Terror: Worldwide Campaign