From the moment Axion's mechanical chassis vanished from Guilliman's sight, a coordinated multi-departmental operation was triggered across Terra. Though the machine moved with preternatural speed, the Inquisition maintained a tenuous grasp on its location; after all, their eyes and ears infested every shadowed corner of the Throneworld.
The Officio Assassinorum had likewise been commanded to assist. An Execution Force had been monitoring the mechanical intruder since it first scaled the Palace walls. They had borne witness to the near-effortless carnage as Axion swept aside the Custodian sentries, handling a Venerable Dreadnought and the Captain-General themselves with terrifying nonchalance.
The sheer structural resilience of the chassis left the assassin cell at a loss. It was a machine; toxins were irrelevant.
Marksmanship? That was a dark jest. Had they seen the Dreadnought's assault cannon? The two Vindicare Assassins were certain that if such a weapon struck them, there wouldn't even be a bruise left to find, only red mist. They harbored no illusions that their specialized Exitus rifles could outperform an ancient assault cannon that was practically a holy relic.
Seeing the ancient Custodian Dreadnought on the verge of destruction at the Iron Man's hands, they were forced to release the only unstable element in their roster: an Eversor Assassin. By their calculus, the explosive yield of its terminal bio-meltdown was the only thing with a chance of making an impact.
The gamble had yielded results. The detonation, potent enough to vaporize a Space Marine, had successfully bought the Venerable Dreadnought a reprieve and managed to "scorch" the machine's plating.
However, the discoloration on the chassis' surface soon vanished, the metal becoming as lustrous as if it had been freshly forged. The machine tilted its head, peering toward the two Vindicares perched on a distant parapet. The assassins didn't wait; they broke cover and vanished into the shadows below.
Axion showed no inclination to pursue. Instead, he turned and strode into the yawning maw of the Great Spire's primary transit corridors. Within minutes, more Custodians and Dreadnoughts arrived to recover the wounded and secure the perimeter.
Trajann Valoris, meanwhile, immediately donned a suit of Terminator armor, leading a fresh contingent of warriors into the heart of the Palace to hunt the intruder.
Simultaneously, Guilliman was attempting to force entry into the inner Palace, only to be blocked by several ancient Dreadnoughts. At this moment, the Custodes' resentment toward the Primarch had reached its zenith.
Guilliman stared at the golden giants blocking his path, his mind racing with frustration. He could not storm the Palace by force; such an act would spawn rumors by morning that the Lord Regent had turned traitor. If such word spread, the Imperium would fracture instantly. His own sons might dismiss such folly, but what of the rest?
Another civil war? The Imperium cannot endure it.
Standing outside the gates, Guilliman was consumed by anxiety but rendered powerless. He knew the Iron Man had no inherent interest in the Emperor; even left unguarded, the Master of Mankind would likely be safe. But the Custodes could not, would not, understand. An unsanctioned breach was an act of war. The Iron Man's warnings would be ignored by the fanatical devotion of the Emperor's Guard, and their stubbornness would bring a catastrophe upon the Imperium, a catastrophe of his own making.
…
"Are you certain?"
"Incredible."
Several of the Dreadnoughts suddenly glanced at one another in a silent vox-exchange. To Guilliman's shock, they stepped aside, clearing the path to the Palace gates.
"Guilliman. You may enter."
Guilliman was stunned by the sudden reversal. What has happened? Has my Father issued a decree?
As he crossed the threshold of the high walls, a figure shrouded in the heavy, hooded robes of the Adeptus Astronomica stood waiting at the entrance.
"Lord Regent, please follow me."
Guilliman pressed for answers, his voice thick with confusion. "What is the meaning of this?"
The mortal leading the way lowered his hood, revealing the stark brand of the Hollow Mountain upon his brow. His withered features and the array of psychic dampeners adorning his robes marked him as "kindling," a high-grade psyker destined to be consumed by the Golden Throne in short order.
"My Lord, a moment ago, the entirety of the Hollow Mountain experienced an anomaly. Every psyker beheld the Emperor's majestic form. Thousands of voices rose in a singular, harmonized choir, speaking His will. The Emperor Himself has decreed that the Custodes must cease their obstruction of the Iron Man. He has commanded that you personally escort the machine to His private chambers."
Guilliman stared in utter disbelief.
The psyker produced a portable slate, displaying surveillance footage from the Sanctum Imperialis. The secret fortresses housing the psychic kindling lay deep within the Palace, separated from the Imperial Sanctum only by the Eternity Gate.
The images left Guilliman breathless.
Every psyker in the fortress was being flooded with a titanic surge of golden energy, their bodies writhing in agony. Those of lesser psychic grade were reduced to ash in a heartbeat. Yet the survivors began to speak in a terrifying, unified unison.
The voices were ethereal, saturated with a holy, terrifying will. Though the mortal ear could not truly comprehend the majestic echoes from beyond the Warp, every soul present understood the command.
It was the will of the Emperor.
He spoke of His hopes and fears for the human race; He issued warnings and portents. Because the secret fortresses were vital to the Emperor's continued existence, they were under strict guard. The Custodians stationed there had witnessed the miracle firsthand—the divine warning from the Empyrean channeled through mortal throats.
As the golden light in the footage faded, more than half of the psykers collapsed into death. Those of higher grade who remained were left withered and ancient, as if centuries of life had been siphoned away in an instant.
The man leading Guilliman was one of those survivors. He claimed the Emperor had granted him a specific task: to guide the Primarch through the darkness hidden beneath the Palace. Initially, none had believed him, but the miracle was too profound to ignore.
The psyker proved his claim by demonstrating an impossible knowledge. He navigated the labyrinthine subterranean levels and the mysterious ancient dungeons, areas he had never visited in his life, reaching the surface to find Guilliman with the unerring precision of the Emperor Himself.
In the face of such undeniable divinity, even Guilliman had to believe.
As Guilliman followed the psyker into the depths, Axion's chassis noted a shift in the Custodians' behavior. He had encountered several patrols while wandering the subterranean halls. The machine made no effort to hide, walking openly through unknown corridors and investigating sealed rooms.
The Custodians, however, no longer reacted. They stood like statues, looking through him as if he were a ghost. Axion ran multiple diagnostic scans on his systems and the surrounding space. Confirming no external anomalies were affecting his sensors, he ceased his investigation and accelerated his search through the dark foundations of the Palace.