Nunc Finis

The campaign known as 'Nunc Finis, was an Imperial defensive campaign conducted by multiple companies of the Argent Leviathans Space Marine Chapter. Following the destruction of Cadia and the subsequent formation of the Cicatrix Maledictum, the bulk of the Chapter was cut off in the Segmentum Tempestus against an invading Ork WAAAGH!, while four of the Chapter's companies were trapped in the Imperium Nihilus in the Norian Sub-Sector, defending Imperial worlds from ever-increasing attacks by the Forces of Chaos and their daemonic allies. It would take several years for the remainder of the Chapter to reunite with their beleaguered brethren and help end the threat of Chaos in this vitally important regions of space.

History
As the end of the millennium was nearing, the Argent Leviathans were split between two different Segmentums. The bulk of the Chapter's forces were in the Segmentum Tempestus, fighting a bloody crusade against an Ork WAAAGH!, while the 4th, 6th, 7th and 9th Companies were defending the Segmentum Obscurus against an increasing amount of Chaos incursions.

When word reached the Chapter of Abaddon the Despoiler attacking the Cadian Gate, the bulk of the forces began to make their way to Cadia ordering the companies within the Segmentum Obscurus to retreat to the Norian Sub-Sector and protect it against chaos attacks. However, due to the warp instability at the time, the bulk of the forces never reached Cadia in time and instead made an emergency exit from the warp after Cadia was destroyed. This action spat the Chapter's bulk out within the Ultima Segmentum where they head of the resurrection of Roboute Guilliman. Upon hearing this the bulk of the Chapter quickly mobilised to join the resurrected Primarch's Indomitus Crusade.

However, these were the lucky ones as the 4th, 6th, 7th and 9th Companies were now trapped within the Imperium Nihilus and were forced to defend the Norian Sub-Sector from daemonic incursions, before slowly being pushed back further and further before finally making their last stand in the Caerulian System.