Terran Crusade - The Sorrow: It was during the seventh solar month of the campaign to reconquer Ultramar that the first cases of a mysterious new sickness were reported. Throughout the Drohl, Talassar and Parmenio Systems, Ultramar Defence Auxilia found themselves weeping uncontrollably. In the midst of battle, warriors were blinded by endless streams of viscous, stinking tears that gummed their eyes open and soon turned them red raw. Overcome by sorrow, sufferers wailed and wept for solar days on end. In the worst cases, the so called "Weepers" were permanently blinded as their infected eyeballs festered and rotted from their skulls.The disease, soon named the Sorrow, or the Weeping Plague, spread with alarming rapidity. Its vector was believed to be an infestation of tiny, biting mites that were found amidst rations, squirming inside uniforms and ammunition packs, and even spilled from the pages of opened Imperial Primers. Nothing stopped the mites from multiplying, and no sanitary measure could long keep them out. The siege of Leotold's Keep collapsed thanks to the pernicious influence of the Sorrow, while the previously devastating Ravishol offensive ground to a halt as its human soldiery were reduced to blinded, wailing revenants.Roboute Guilliman hastened to Talassar, leaving the war in the Prandium System to the command of Chief Librarian Tigurius and Inquisitor Greyfax. Guilliman knew that only mortal soldiery had been afflicted with the Weeping -- no warrior of the Adeptus Astartes or tech-thrall of the Mechanicus had fallen prey to the sickness as yet. Furthermore, though they were not absolutely immune, only a very few cases had been reported amongst the ranks of the Adepta Sororitas. Some ascribed this to the presence of the Living Saint amongst the reconquest forces, but more believed that it was the enduring faith of the Battle-Sisters that protected them from sickness.Whatever the truth, Guilliman did not fear the terrible disease, but was instead far more concerned for the fate of his mortal soldiery. The Primarch arrived upon the world of Ravishol expecting nothing but sadness and horror. Guilliman's shock, therefore, was as great as anyone's when instead he brought a miracle.Braving the hammering flak screens of the Iron Warriors encampments on the circuit-plains, Guilliman had his Thunderhawk deliver him to the fortified Imperial encampment in the Soldermask Valley. Over the thunder of the encampment's Servitor guns -- busy keeping the enemy Daemon Engines at bay -- Guilliman ordered the camp's Ultramarine commander to lead him to the sick. There were several thousand of them in this encampment alone, tank crews, artillerymen and infantry soldiers trammelled for their own protection within huge prefabricated sheds. From outside, the muffled cacophony of the Weepers' lamentation was unsettling even for Roboute Guilliman, yet as the shed's armoured doors swung open, the sobbing slowly died away. One by one, the stricken Auxilia rose from their sick beds, blinking in amazement with eyes that could see once more. Even those who had lost their sight altogether subsided with sighs of relief, knowing their first true sleep in weeks. None could explain how, but Guilliman's presence had healed the Weepers.The same thing occurred in three more encampments along the offensive's stalled front. Wherever Roboute Guilliman walked, the Sorrow was driven out and the mites that spread it died until they piled up in black drifts. The medicae and Apothecaries were at a loss, but the Ecclesiarchy were quick to declare the phenomenon miraculous. It was the Emperor's mercy, they bellowed, brandishing their Aquilas, and it shone from His son as healing light.So began long solar weeks of relentless pilgrimage for Guilliman, as he rushed from one site of sickness to another. The Primarch knew that while he was engaged in healing his followers, his attentions were drawn away from the wider war. Yet of all the Emperor's sons, Guilliman was perhaps the most human, and his compassion would not allow him to ignore his followers' plight if he could heal them.Solar days became weeks, during which the Weeping continued to spread and -- worse still -- recur at sites that the Primarch had already cleared. Without Guilliman's peerless genius the reconquest began to suffer, the Chaos forces overturning Imperial victories in the Veridian and Tarvan Systems. All the while, the dreadful Warp Storms that had riven Ultramar and its surroundings worsened further. Soon, whispered the Navigators, the empire of the Ultramarines might be cut off from the wider galaxy altogether, just as it once had ten thousand Terran years before during the time of the Ruinstorm.It was Grand Master Aldrik Voldus who finally confronted Guilliman. In a heated argument, during which the Grand Master dared the Primarch's wrath, he forced Guilliman to acknowledge that which he already knew. Weeks of labour had been for nought. Guilliman was not healing his subjects, for such was not his gift. In the Weeping Plague, Voldus recognised all the hallmarks of Nurgle. Most likely, the Plague God was simply withdrawing his dubious blessings from his victims upon Guilliman's arrival, then gleefully restoring them once the Primarch had moved on. The Lord of Ultramar was playing into the Plague God's hands, his desire to save his people perverted into a never-ending trap of entropy and despair.Though furious, Guilliman accepted Voldus' wisdom. Further, he saw that Nurgle's desire had been to trap him within his own realm, and to keep him from the wider galactic stage. The Primarch realised then that his desire for completeness, for a neat solution and an unsullied Ultramar was, in itself, an echo of mistakes he had made long ago. Nurgle did not wish Guilliman to leave Ultramar because there, the Primarch could be contained like a wasp in a bottle. But this war did not belong to Ultramar alone -- it was a war for the entire Imperium. Guilliman saw that he could waste no more time focussing solely upon his own stellar empire. He must tend, instead, to his father's.With a heavy heart, Roboute Guilliman stopped his efforts to end the Weeping Plague, instead charging his Apothecaries and Chaplains with finding a spiritual cure for what was clearly a spiritual affliction.The Primarch announced his intention to set out upon a great journey. Once before, when the Dark Gods had threatened the Imperium of Mankind, the Primarch of the Ultramarines had reached Terra too late to do his duty. He would not make that mistake again. Guilliman intended to journey to Terra, to kneel at the foot of the Golden Throne and ask his father for guidance.Conscious of the worsening Warp Storms lashing the space lanes of Ultramar, Guilliman announced his intention to make for Terra as soon as a suitable force could be assembled. The Primarch would not travel alone; the galaxy had become a dark and dangerous place, while the attempts by Slaanesh and Nurgle to tempt and trick him had shown Guilliman that his resurrection had drawn the eyes of the Ruinous Powers.The war across Ultramar was still ongoing, however, and with Guilliman leaving, it would require strategically gifted warriors to keep pushing the Forces of Chaos back. As such, Guilliman gathered a select force of Battle-Brothers from the 1st, 2nd and 3rd Companies of the Ultramarines to accompany him to Terra, and gave the honour of their command to Captain Cato Sicarius. He further requested that Grand Master Aldrik Voldus and the Grey Knights of the 3rd Brotherhood join their Crusade. Others pledged their aid to the Primarch's cause, including the assembled strength of the Primogenitor Chapters, and Emperor's Champion Amalrich and his Black Templars brethren. The Living Saint, the Inquisitor and Archmagos Dominus Cawl accompanied the Primarch also -- whatever aid they or the military forces under their command could provide the Primarch would be gladly given. Guilliman gratefully accepted all offers of aid before commanding Marneus Calgar, Chief Librarian Tigurius and Captain Agemman to remain and lead the reconquest of Ultramar.The Ynnari, meanwhile, chose this moment to depart. The Eldar had their own wars to fight, and had already lingered overlong amidst human affairs. Though Cadia had fallen, worlds still remained upon which the Necron-built black pylons stood strong. It was to these that the Ynnari would now attend, directing those of their race who would listen to defend them and thus hold back the expanding power of the Warp.The Celestinian Crusade had come to its end with its objective met beyond its heroes' wildest expectations. In its place, the Terran Crusade would begin. Mere solar days after Guilliman made known his intentions, the Imperial fleet set out, engines burning hot as they began the long journey to the cradle of Mankind.The audience chamber in the Fortress of Hera was empty but for Yvraine, the Visarch, and Guilliman. In a matter of solar hours, the Terran Crusade would depart Macragge, yet the Primarch had found a few moments to speak to the Ynnari leaders alone. Even after solar weeks of mutually fruitful alliance, most warriors would have been cautious of standing alone in the presence of two such sinister and powerful xenos. Guilliman was not most warriors."It will be a long and dangerous journey", said Yvraine. "The galaxy grows darker by the day. Have a care, Primarch. You may have cheated death once, but you are not invincible."Guilliman nodded solemnly. "Can I say nothing that will convince you to join us on our road? I have come to value the strength of you and your warriors greatly these past weeks.""You cannot", Yvraine replied. "Already we have given you the gift of rebirth, not to mention a number of our peoples' lives. Is that not enough?""It is a debt I'm sure won't be forgotten", said the Primarch. "Before you depart, tell me this. Cawl may have fashioned the armour that I wear, but it was not he alone who ensured my resurrection, was it?"Yvraine smiled demurely. "His technology would have healed your physical wounds, Roboute, but you and I know that the worst damage had been done to your soul. So no, Primarch; it is by the grace of Ynnead that you stand once more amongst the living. If you wish to remain, however, I would caution you against removing your war-plate. Not that you could easily do so."A flicker passed across Guilliman's features at this, a faint ghost of pain well-hidden, swiftly replaced by a stony mask of duty."I could press you for greater insights into the powers that brought me back, and assurances against any taint in their nature", said Guilliman, noting how the Ynnari stiffened their postures at this. "But I suspect that our newfound understanding is of more value to my father's realm than my own satisfaction. And that those answers would not come easily."Yvraine inclined her head, while the Visarch silently eased his hand away from the hilt of his blade."Thus, instead, I shall simply wish you victory in your ongoing battles against our mutual foes.""May you walk with fortune, Roboute Guilliman", said Yvraine. "And know that we shall stand together in battle again, before whatever end befalls us."The Visarch offered an elaborate warrior's salute to Guilliman, who nodded curtly in return before the Eldar turned and swept gracefully from the chamber."No doubt we will", murmured the Primarch thoughtfully, watching the enigmatic xenos withdraw. "As long as it serves your needs..."