"So, what you're saying is..." Guilliman began, his voice dropping into a low, tired register as his mind processed the historical horror story Gerhard had just laid out. "The greatest existential threats to the stability of the Imperium over the last ten millennia did not always emerge from the Eye of Terror. They came from the High Lords themselves."
The Primarch paced the length of the chamber, his heavy boots clicking rhythmically against the marble floor.
"A Grand Master of the Officio Assassinorum conducting a systematic purge of the senatorial class to seize absolute control. And an Ecclesiarch whose psychotic delusion plunged the galaxy into a civil war so vast it gave birth to an order of female devotees. All without a single daemon crossing the veil."
"Precisely," Gerhard said, leaning back and crossing his arms. "It's like Joseph Conrad said, 'The belief in a supernatural source of evil is not necessary. Men alone are quite capable of every wickedness.' Chaos didn't have to bleed the Imperium dry. Human nature, unchecked ambition, and bureaucratic rot did most of the heavy lifting. The Dark Gods just sit back and watch the show. Although it was a bit of a gamble on everyone's part."
Guilliman stopped by the map table, his violet eyes flashing with a cold, analytical brilliance. The deep despair that had threatened to swallow him only moments before was entirely gone, replaced by the familiar, comforting weight of a grand logistical problem.
"Then my course of action must be two-fold. To fix a machine this broken, one cannot simply polish the hull while the internal gears grind themselves to ash. I must wage a war of absolute liberation across the stars, but first, I must reclaim my home. If Macragge falls, our foundation is dust."
He looked directly at Gerhard, the phantom image of the Emperor fading from his perception, replaced by respect for the unique mortal standing before him.
"Wider galactic matters will have to wait. We clear the system. We secure the realm of Ultramar. And you, Gerhard... you will remain at my flank."
"I actually have some things you might be interested in."
Guillliman looked at Gerhard, interested. They hadn't shared all that much about one another, and the Primarch was very interested in Gerhard's life so far; he already understood that there was a lot of depth to the 'mortal'. So if he said there was something he might be interested in, then he believed him.
"It's called: Excel. A tool of ages past, but probably worth more than entire planets. It is the galaxy's most versatile canvas for turning messy data into organised, actionable logic."
"..."
"Tell me more."
.
The liberation of Macragge was to be the first step, a blistering campaign that lasted a little over a month. Roboute Guilliman moved across his homeworld like an unstoppable force of the Emperor's will, driving the forces of Chaos before him like cattle. Yet, while the Primarch orchestrated global war movements, it was in the tight, grinding hinges of the frontline where Gerhard's endless resourcefulness reshaped the campaign and caught the further attention of the Avenging Son.
During the lightning offensives to clear the Valley of Laponis and the shattered domes of Magna Civitas, the loyalists slammed into reinforced batteries of intricate Iron Warriors siege weaponry. The semi-sentient artillery engines were spewing devastating salvos that pinned down entire companies of Ultramarines.
It was here that Gerhard integrated his specialised cell into the vanguard.
While Marneus Calgar coordinated the heavy armoured columns, Gerhard used his [Presence Sense], [Danger Sense] and mini-map to map out the mechanical blind spots of the heretic fortifications.
Moving with an uncanny, unnatural swiftness that bypassed conventional or even unconventional traps, Gerhard cast localised [Psionic Mana Shields] to anchor the advancing front. Beneath the shimmering blue domes of his energy barriers, Ultramine strike teams advanced completely unscathed by shrapnel, shells and bombs, planting melta charges and bolter fire directly into the whip-fisted overseers' artillery hubs.
When Grand Master Voldus and the silver-armoured Daemon hunters of the 3rd Brotherhood launched their strike against the corrupted city of Collosae, they found themselves playing a lethal game of cat-and-mouse with the Night Lords.
The traitors had veiled the metropolitan hab-blocks in an unnatural Warp-darkness, rendering traditional sensors useless and giving them their preferred fighting environment.
Gerhard, however, would have none of that.
Stepping into the dark, Gerhard nullified its very source. By flaring his [Blank] power in controlled, rhythmic pulses alongside the Sisters of Silence, he tore away the Warp-infused shadows over large swathes of hab-blocks, exposing the vicious ambush lines of the Night Lords.
And no matter where he was, no matter how long he fought at a time, Gerhard always could do more, fight longer, have more ammunition and weapons for his fellow warriors to use. He was an unstoppable supply line and force all in one, and the Chaos forces didn't know how to handle him.
"Target the upper balconies," Gerhard's voice snapped across the localised vox, his tactical appraisal feeding directly into the Ultramar Defence Auxilia networks. "A series of Night Lords have been spotted on the long-range augur arrays. Flush them right."
The usual terror-inducing hit guerrilla-like warfare of the Night Lords turned into a sad cat-and-mouse game, where the mouse always seemed to see the mouse's next move ahead of time.
With the darkness lifted, Voldus's paladins caught the traitors flat-footed. Gerhard himself spearheaded a flanking manoeuvre, in his Doomslayer set-up, his Anathame blade hummed through the air as it bisected a Night Lord's champion before the heretic's jump pack could even ignite.
The traitorous Space Marine was too used to igniting fear from his human prey that he couldn't hope to understand what he was seeing. All he felt was the immense dread of what was the most powerful blank since Jenetia Krole and the destruction of his soul a moment after.
The mysterious blood ritual the Khornish forces were conducting was halted before it could come to fruition, stripped of its warp energies by the localised null-field Gerhard maintained.
Throughout these engagements, Guilliman listened to and reviewed reports. The Primarch's strategic mind, a machine of peerless, four-dimensional logic, noted how effortlessly Gerhard adjusted to the fluctuating, multi-theatre operational parameters.
Gerhard wasn't merely a powerful combat asset; he was structurally efficient. He understood the importance of supply lines, pinpointed structural weaknesses in Daemon Engines, and knew exactly where a single, precise application of force could collapse an entire enemy flank.
And most importantly, he was seemingly fearless, but not arrogant or reckless. He told him that he and Guilliman were most likely the last in the galaxy with the power of 'common sense'. And the Primarch was starting to realise just how resourceful Gerhard truly was.
.
When the outer world was finally cleared, and the invasion craft of the Black Legion were reduced to burning scrap in the void, the high leadership gathered in the fortress-monastery's grand strategium.
First Captain Agemman, Chapter Master Calgar, and Chief Librarian Tigurius surrounded the primary hololithic display table. Standing right beside Roboute Guilliman, closer than many veterans deemed traditional for a newcomer, was Gerhard.
As Agemman detailed the lingering pockets of resistance near the Magletine Highlands, Guilliman shifted his violet gaze to the mortal warrior.
"Gerhard," Guilliman spoke, his voice clear and carrying great weight. "Your deployment parameters in the Laponis sectors showed an intuitive grasp of Iron Warriors defensive geometry. Where do you chart their retreat paths and next attack points?"
Gerhard stepped forward, completely unbothered by the monstrously powerful aura of the Primarch or the still slightly suspicious glares of the Ultramarine captains who were not used to seeing a mortal held in such high regard.
Gerhard tapped the hololithic projector, superimposing a network of subterranean aqueducts beneath the Pharamis Ocean grid.
"They aren't retreating to the void, Primarch," Gerhard said smoothly, pointing to a structural fault line. "Their heavy armour is attempting to slide beneath the continental shelf to fortify the deep-sea thermal vents. If we route Chronus's tank columns here, we catch their logistical tail before they can submerge."
Guilliman stared at the map for a single picosecond, his super-human mind running ten thousand simulations simultaneously. A rare appreciative nod broke the Primarch's stone-faced intensity.
"An impressive assessment," Guilliman declared. "Captain Agemman, execute the shift. Lord Gerhard's cell will retain tactical autonomy to act as our apex line-breaker."
With those words, Gerhard's positioning within the highest echelons of the Imperial war machine was solidified. He was no longer just a mysterious anomaly who fought inside the Temple of Correction; he was a recognised man of importance, a resource of objective, logical value sitting directly at the right hand of the Avenging Son.
Something considered impossible and highly unusual.
Guilliman pressed the advantage across the rest of the planet, leading victorious attacks against Valmari, Mount Tarphus, and the frozen terrain of the Gallinus Pass. The Ultramarines swept through everything in their path, flawlessly blending their elite skill and discipline with the visionary, multi-layered battle plans of their Primarch.
Directly behind the conquering spearheads came the massive regiments of the Ultramar Defence Auxilia. Moving with perfect logistical efficiency, they immediately dug in and heavily fortified every newly secured territory. Because of this, whenever the forces of Chaos tried to launch a desperate counter-attack, they slammed into overwhelming, unbreakable resistance.
One by one, the Chaos warbands were outmanoeuvred and systematically destroyed. Even the traitors who managed to scramble onto ships and flee Macragge found absolutely no safety in the void. Their invasion craft were quickly surrounded by the waiting Ultramar Defence Fleet and reduced to drifting, burning scrap metal.
Finally, after long, brutal weeks of non-stop fighting and a staggering toll of dead, the world of Macragge was liberated and fully reclaimed. Standing side-by-side upon the high ramparts of the Fortress of Hera, Guilliman and Gerhard looked out over a secure homeworld. The first great victory of a new age was won, and the realm of Ultramar was firmly back under the control of its rightful master.