Upon every world that the comet passed, the Cholercaust would descend and destroy its inhabitants entirely, in the name of the Blood God. The Chaos forces consisted of World Eaters led by Umbragg as well as Chaos Space Marines from The Cleaved, Skulltakers, and Thunder Barons. They were supported by Khornate Daemonic legions led by the Daemon Prince known as The Pilgrim as well as forces of The Lost and the Damned. They were opposed by the Excoriators' 5th Company as well as the Sisters of Battle of the Order of the August Vigil. The ultimate goal of the campaign was to reach Terra itself.
On the Cemetery World of Certus-Minor, the Excoriators' 5th Company, led by Corpus-Captain Zachariah Kersh, stood against the vast Crusade. They were almost wiped out by the Chaos forces in the attempt. Just when all seemed lost for the Imperial defenders, the mysterious Legion of the Damned arrived, which was able to decisively turn the tide and defeat the Chaos forces.