Ultramar - Spear of Espandor Counterattack: At the end of the first phase of the Indomitus Crusade to stabilise the Imperium Sanctus, following the Battle of Raukos, Lord Commander of the Imperium and Imperial Regent Roboute Guilliman announced his intention to return to his home realm with thousands of Primaris Space Marine reinforcements and drive back the Chaos assault. First, he cleansed the Hive World of Ardium in the Maccrage System of its Death Guard occupiers. In the course of that operation he learned that Mortarion was using the ancient artefact known as the Hand of Darkness to craft Plague Engines that were re-animating the dead and turning them into Plague Zombies. Guilliman destroyed the Plague Engine on Ardium and freed the world from the influence of Nurgle.His next destination was Maccrage itself, his ancient homeworld. He and his Astartes reinforcements, including the Primaris Marines, brought much-needed relief to the weary populace and defenders. After taking stock of the dire situation, Guilliman reorganised the Ultramarines and their mortal auxilia and launched a large-scale counterattack against the invaders. Several Ultramarines Successor Chapters also joined the fight at their primarch's behest, their Chapter fleets engaging the Death Guard and doing their best to keep Ultramar's shipping lanes and supply lines to the broader Imperium safe and secure.Guilliman first set his eyes on the Espandor System as part of what he named his "Spear of Espandor" campaign, because it served as the main supply line for the Death Guard invasion from the Scourge Stars. He retook each of the lost worlds in the system and destroyed the Plague Engines that were raising the endless tide of Plague Zombies on each of its worlds. After a ferocious battle in which the Ultramarines Chapter found itself fighting side-by-side with their Primaris Astartes brethren for the first time, the forces of Nurgle were routed from Espandor. Guilliman decisively ended the battle by slaying the Great Unclean One Qaramas with the Emperor's Sword and destroying the last Plague Engine in the system. The Espandor System had been cleansed of the taint of the Plague God and the forces of Nurgle were now cut off from their base in the Scourge Stars.With their supply lines to the Scourge Stars cut, their Plague Engines disappearing and slowly eliminating the constant tide of undead reinforcements, and new Imperial reinforcements pouring into Ultramar with each passing solar day, Mortarion found himself on the wrong side of what had become a war of attrition. Guilliman had successfully cut the Death Guard off from resupply and would now proceed to cut their forces to pieces, one star system at a time. With this in mind, Mortarion decided to throw all his remaining forces at a single target in the hopes of reversing the tide.Maccrage was still too heavily defended for the forces of Nurgle to carry out a successful assault, so Mortarion decided that the Plague God's servants would target the Ultramarines training world of Parmenio. This battle saw the biggest armoured clash between the Chaos and Imperial forces during the war.The largest star fort in Ultramar, Galatan, attempted to provide support but was engaged by Typhus' Plague Fleet and was boarded by a contingent of Traitor Marines, leading to the death of the Novamarines' Chapter Master Bardan Dovaro in the vicious fighting.On the surface of Parmenio, however, the Ultramarines slowly gained the upper hand. Guilliman killed Ku'gath's lieutenant, Septicus, and shattered his Daemonic Plague Guard, an action that finally gave the Emperor's servants the upper hand in the conflict. With the campaign at last in hand, Guilliman turned to the hunt for his traitorous brother.