The radiation-blasted world of Kol in the Signus Cluster played host to some of the most secretive battles of the Horus Heresy. Here the Legio Custodes would take the fight to Traitors, rebellious members of the Solar Auxilia, and even the accursed daemonic spawn of the entity known as Slaanesh.

This gaming supplement for Warhammer: The Horus Heresy details the actions of the Legio Custodes in the Signus Cluster, the battle they fought on the cursed world of Kol, and the fate of those that died there. In addition to the tale of this conflict, this journal contains a Legendary Mission to refight key moments in the iconic war for the Signus Cluster. It also contains rules for all of the factions involved in that struggle, including rules which allow players to field the Daemons of Slaanesh in the Horus Heresy for the first time.