- "Character is forged upon the anvil of war, hammered by circumstance and shaped by will."
- — Warmaster Slaydo.
Slaydo was the chief architect and first Imperial Warmaster of the Sabbat Worlds Crusade. Slaydo was killed in action during the Imperial military campaign to reclaim the world of Balhaut after engaging in single combat with the Forces of Chaos' commander in the sector, the Archon Nadzybar. The Crusade ultimately triumphed on Balhaut and Slaydo was replaced by his chosen heir, Macaroth, who became the new Warmaster of the Sabbat Worlds Crusade.
Following the disastrous loss of the Sabbat Worlds in 741.M41 to the Forces of Chaos, there were many suggestions within the Administratum that an Imperial military expedition should be sent to liberate the besieged sector. But many officers within the high echelon of the Imperial military had little or no enthusiasm for such an undertaking, save for then-Lord Militant Slaydo. A tactical genius, Slaydo was a capable Imperial commander who had already established a reputation as a skilled leader during the successful Khulan Wars (752-754.M41). Capitalising on his popularity with the rank and file of the Imperial Guard, the Lord Militant petitioned the High Lords of Terra for the honour of leading such a Crusade. He had supported taking such action as early as 732.M41, as he felt a strong passion for the liberation of the hard-won territories of the Sabbat Worlds that had been so poorly defended. Many of his senior commanders and aides relate that Slaydo believed the loss of that sector to be a crime against the Emperor Himself.
In 755.M41, the High Lords granted Slaydo the rank of Warmaster and charged him with the sacred duty of carrying out the monumental task of liberating the Sabbat Worlds. Slaydo's subsequent elevation to this esteemed position was the envy of his fellow Lords Militant, an envy which was quickly tempered by the realisation of the task that had been set before Slaydo. The Warmaster's only overriding fear was that at his advanced age (150 Terran years old at the Crusade's start), he would not live to see the eventual victorious completion of such a massive campaign. Unfortunately, this prescient vision would prove to be accurate.
The Warmaster met his fate on the world of Balhaut in 765.M41, during his final push to take the heavily contested planet. Taking up his Power Sword, the Warmaster personally led the first attack wave against the Palace of the Oligarchy, where he hoped to come face-to-face with the Chaotic commander, Archon Nadzybar, the spiritual leader of the Forces of Chaos within the Sabbat Worlds Sector. On the tenth day of the campaign on Balhaut at the eighteenth hour, Slaydo's command force encountered the Archon and his elite bodyguard on the Western Palisade. The Warmaster and the vile Archon soon joined in furiously intense single combat.
The fight between the two forces lasted for only between 6 and 11 minutes. During the hand-to-hand fighting, Slaydo took two mortal wounds that he somehow managed to ignore, maintaining the initiative, before delivering a lethal blow to the Archon, who fell back dead. Imperial Guard units valiantly defended their own mortally wounded commander, and sent many cultists to their deaths. The Warmaster was found by his troops already close to death, lying on the marble floor of the West Atrium. He was far beyond any medical help as his grievous wounds were clearly mortal.
Warmaster Slaydo managed to live long enough to see the Imperial victory on Balhaut completed, although the pacification efforts would continue for a considerable amount of time. His premonition about himself not living to see the successful completion of the Crusade had proved accurate, though many witnesses report that he died contently, resigned to his inevitable fate to die on Balhaut as if he had fully expected it and was glad that it could come in the midst of a victory for the Emperor. His last words were "I am done, and yet I am undone."
It is often noted by Imperial historians that Slaydo's primary anxiety lay, not in his fear of a premature death, but in who would be his eventual successor in carrying on the Crusade. The Warmaster recognised that there would more than likely be political infighting amongst the Lords Militant for his command once he was gone. He knew the Crusade could not afford to be riven with internal dispute and that it would take a strong leader to capitalise on a great victory. Therefore, the dying Slaydo appointed the young Marshal Macaroth to be his successor as Warmaster. This appointment by the dying Warmaster brooked no argument from the Lords Militant, but officers like Cybon, Hechtor Dravere and others were incensed at Slaydo's decision, as they regarded the newly-appointed Warmaster as too young and too junior to take on the responsibility of leading the Crusade. A period of bitter political jockeying ensued to weaken the new Warmaster before he could grasp a firm hand on the reins of command and the loyalties of the Crusade's troops, but Macaroth managed to cling tenaciously to his rightful position as the newly appointed senior commander of the Sabbat Worlds Crusade.
Warmaster Slaydo was a man of great personal faith in the Emperor of Mankind's cause and held a particular affection for the legacy of Saint Sabbat, who was his personal patron saint. Slaydo had long felt it a personal duty to conduct the liberation of the Sabbat Worlds from the Forces of Chaos. Over two decades before the Crusade had even commenced, many of his senior commanders and aides related stories of Slaydo's passion for the cause of the Saint. It was later noted that even in the initial planning stages of the Crusade, Slaydo believed that he was "walking in the path of the Saint," an oft-overlooked reference to Saint Sabbat's original campaign to bring the Sabbat Worlds into the Imperium of Man during the 35th Millennium, and her great advisor, Faltornus, whom Slaydo especially admired. The Warmaster believed in paying great respect to the wisdom and beliefs of the figures that had inspired him to undertake the Crusade in the first place. When he went to meet his fate on Balhaut, he went to his death with quiet contentment and resignation as if he had been fully expecting it. Some even claim that the Warmaster knew when his death would occur as early as 756.M41. Following his triumphant final battle, Slaydo's body was laid to rest with full Imperial honours on Balhaut, housed in a large mausoleum known as The Honorarium.