Idolatros

The Idolatros system, situated in the Somnium Stars, was a star system without attested coordinates. In the early 42nd millennium it became the site of the Battle of Idolatros, recorded as the last great battle of the Arks of Omen campaign.

Within the system, the Chaos entity Vashtorr had assembled Wyrmwood, a mechanical daemon world built from the remains of Caliban. There, Abaddon’s fleet fought the Dark Angels and their returned primarch, Lion El’Jonson, in the battle that marked the Arks of Omen campaign’s culmination.

The battle was fought within the Idolatros system itself, and not on Terra. It stood as the last great engagement of the Arks of Omen campaign, bringing together Abaddon’s fleet, Vashtorr’s assembled daemon world, and the returned primarch in a single confrontation.