On Rhodes' side, the battles that followed could be described as a string of swift victories. Upon arriving at each planet, Rhodes would dispatch an emissary to investigate.
First, they asked whether the planet still swore loyalty to the Emperor and to the Imperium. If the answer was yes,
then a survey team—organized by Guilliman—would be sent to conduct a full audit of the world.
Rhodes' expeditionary force carried many such survey teams. Their duties were to check for signs of Chaos corruption, xenos infestation, and any acts of treachery against the Imperium. Once a planet was confirmed safe and loyal, Rhodes would leave behind one survey team; they would convert into administrators to assist the planet's governor.
If a planetary governor committed crimes, abused their authority, or oppressed the populace, the survey team would submit a request to Rhodes for armed intervention.
Mortal auxiliary regiments would be deployed alongside Adeptus Astartes to sweep in, depose the governor on the spot, and execute all local nobles.
A new planetary governor would then be selected, administrative personnel stationed to manage the world, and a line of communication established with Holy Terra.
As for planets seized by xenos or corrupted by Chaos, Rhodes showed no mercy either, sending his forces to exterminate the xenos or Chaos presence.
The armies led by Sanguinius, Rogal Dorn, and Vulkan acted in much the same way. Dorn's methods were stricter, while the Fire-born Legion was more lenient.
As for Sanguinius, the Great Angel, he proved the most beloved—his mere arrival on a world would bring immediate cheers from the people.
A pair of golden wings, even more stirring and compelling than his former white ones.
On the Imperium Nihilus side, the Lion, Lion El'Jonson, led his First Legion; together with Horus's 16th Legion, the Shadow-Moon Direwolves, they steadily consolidated Imperial power.
With the help of Aeldari Webway routes, the new-era Astartes technology spread to Horus's side. Leveraging the power of cosmic beast, they could even purify some Chaos Astartes from the Astral Imperium.
Those who could be saved were restored to normal humanity; those too far gone Horus refused to accept, granting them the greatest mercy—an honorable death in Chaos's wars.
Returning to the Golden Throne, their souls redeemed—this was the best end they could hope for.
Across the Sanctified Marches of the Imperium, every star system belonging to the Imperium was reclaimed by Rhodes' forces one by one.
The Unyielding Crusade achieved unprecedented results. Tyranids, Orks, even Necrons—anything that stood in the way was trampled under Imperial might.
For a full ten years, Rhodes lived aboard his flagship, waging a grand crusade. His and Elena's second child was born aboard the ship—a healthy boy—giving Stark a younger brother.
Rhodes joked the child was a son of the void, born on a starship—just not in the warp.
Also guarded by a cosmic beast like his brother, the newborn bore within him a nascent beast of his own—a giant bird.
The child did not inherit both ice and fire like his brother, but fully inherited Rhodes' flame aspect.
He possessed the Fire of Rebirth and the devastating Flame of Annihilation. Rhodes named him Sterne, signifying a child born while journeying among the stars.
In terms of aptitude, the child matched his brother—an innate super-lifeform with immense potential. His gene-seed could likewise found an Astartes legion.
His birth sent the entire expeditionary fleet into celebration. The mortal troops cheered.
They had witnessed history—a crusade to rival the Great Crusade of ten thousand years ago—and the birth of a Primarch.
Clergy of the Imperial Cult and Sisters, including Battle Sisters and others, issued proclamations to all worlds Rhodes had conquered.
All worlds taken by Rhodes or the other Primarchs, along with the rest of the Imperium, sent their congratulations. Even the Emperor on Holy Terra and Guilliman sent their well-wishes.
Rhodes answered them all—every congratulation received a reply. Even ordinary planetary governors got an eldritch-voice response penned by his secretary on his behalf.
During this conquest, Rhodes granted resource-rich worlds to various Chapters within his legion.
These would serve as recruiting homeworlds. Solely relying on his own domain for recruits was unrealistic, so he split off his legion's Chapters.
These Chapters would garrison their assigned worlds. If summoned, they would deploy at once; otherwise, they would hold their posts.
Every ten worlds' worth of Chapters formed a Brigade, overseen by a Brigadier. The Brigadier, in turn, was appointed from Rhodes' Deputy Legion Commander.
By now, Rhodes' gene-sons numbered over 1.5 million, surpassing even Roboute Guilliman's former lead. (Even without the reforged Astartes, the Thirteenth's combined progeny across all forces exceeded a million; some 75% of the Imperium's Chapters trace their gene-seed to Guilliman.)
Rhodes' firstborn, Stark, turned eighteen in the twelfth year of the Unyielding Crusade—now a two-meter-tall young man.
Working in tandem with his cosmic beast, he could transform into a four-meter Primarch state, or a sixty-meter giant super-lifeform.
With his coming of age, phase one of the Unyielding Crusade officially concluded. The Sanctified Marches were completely reclaimed by Rhodes and the other Primarchs.
All planets and worlds returned to the Imperium's embrace, linked by the Astronomican's light from Holy Terra.
In the Sanctified Marches, all xenos forces, Chaos incursions, and embattled worlds received reinforcements; new flashpoints would be addressed by the garrisoned Chapters nearby.
Across the Imperium, a standing contingent of Astartes was still necessary. Without guardians, worlds were vulnerable to Chaos attack.
In truth, if fully developed, even a single habitable planet in a star system could sustain a Chapter.
With phase one complete, Rhodes took time to bring his son back to Holy Terra.
The Emperor was to invest three new Primarchs—two of them Rhodes' sons.
The second son, raised aboard ship, had now turned thirteen; phase one of the Unyielding Crusade had taken Rhodes fourteen full years.
"Father! Is that Holy Terra?" asked the thirteen-year-old Sterne, seated beside Rhodes.
Born into the stars, he had spent his childhood aboard a starship or on other Imperial worlds.
At each world, his father and mother took him planetside to tour. He saw countless Imperial worlds—agri-worlds, forge worlds, hive worlds, shrine worlds, even death worlds.
He had also seen many xenos foes; those hateful enemies of mankind were slain by his father's gene-sons.
"That's right. This time, you two will go together to Holy Terra. You'll be invested as a new Primarch, and your brother will receive his own Astartes Legion," Rhodes said, ruffling his second son's hair.
The main purpose of this investiture was to found an Astartes Legion for his son.
His eldest, Stark, had fully matured genetically; his gene-seed could be extracted immediately to found his own Legion.
Guilliman had already prepared a cohort of youthful candidates aged between 10 and 15.
"When will I get my own Astartes and march to war like my brother?" Sterne asked.
"Not long. You're already thirteen. In five years, you can have your own Astartes Legion—by then your genes will be fully stable," the elder brother, Stark, answered.
When his brother turned eighteen, he too would found his Legion.
Following their father into battle these past years, Stark had donned power armor at sixteen—two years earlier—under his father's orders,
fighting alongside his father's gene-sons and taking part in multiple engagements.
He had long yearned to one day lead his own gene-sons in battle for the Imperium of Man, making his father proud.
That day had finally come: on Holy Terra, he would receive his own Astartes.
"Father, aside from me and my brother, has any other Primarch just come of age? I heard there will be three Primarchs invested this time," Sterne asked.
"That is classified. You don't need to know the details yet. Just know that two years after your brother was born,
the Emperor created another new Primarch. He turns sixteen this year and will also found his own Astartes," Rhodes said.
The one being invested alongside his two sons was none other than the Aeldari war god.
Under the Emperor's tutelage, the Aeldari war god had grown, and could now appear publicly as a Primarch.
It was almost comical: the Emperor had poached the Aeldari's champion—turning their war god into his own son, and an Imperial Primarch besides.