Guilliman's idea was sound. All the primarchs had benefited greatly, but Rhodes's wife Elena most of all.
The Cosmic Frost Leopard had raised her soul to the level of a basic demigod, making her a true super lifeform.
As a super lifeform, her gene-seed had reached the mortal limit—true super-evolution.
"I agree, Guilliman, Rhodes. Now my gene-seed can make my sons even stronger," said Lion El'Jonson.
Primaris Space Marines were created with special technology, but gene-seed was always the foundation, forming the template for all augmented organs.
Elena nodded; now her Sisters of Battle rivaled the new Primaris Marines.
Matching the Primaris would still take much work.
But with her evolved gene-seed, extracting new seed would make her Sisters even more powerful.
"So the old gene-seed can be retired—we don't need it anymore," Sanguinius said.
With new gene-seed, the Astartes could be improved again, combining Primaris tech with the new gene-seed.
"It's not that simple. The super-evolved gene-seed can indeed be implanted in your sons, but can normal humans withstand it?
You're now super lifeforms, and at the top tier. Ordinary mortals can't handle your gene-seed."
That's a huge problem—mortals can't handle super lifeform gene-seed.
When Rhodes strengthened three monsters, his body was already at primarch level. After becoming a super lifeform, he dared not extract his own gene-seed for his children, as mortals would simply break down.
Giving them this gene-seed would cause total genetic collapse; the mortal limit is the primarch gene-seed.
"Besides, you've evolved, but what about Malcador, Leman Russ, Rogal Dorn, Jaghatai Khan, and Corvus Corax's legions?" Rhodes asked.
Those primarchs hadn't returned yet! Deathwatch was fine, as they recruited from all legions, but the remaining loyalist legions would be in an awkward spot.
"Primaris Marines are now much stronger than regular Astartes. Perhaps we could upgrade those who are already Space Marines with the new gene-seed," Horus suggested.
It was a compromise. Normal mortals couldn't take it, but what about those who weren't normal?
Astartes are already demigods, and those upgraded to the new standard are at Custodes level.
The other primarchs looked troubled—Rhodes was right, mortals just couldn't survive this power.
Would the evolved gene-seed go to waste, or would the old seed have to be used?
"That could work. Let's discuss it with the Emperor and have my scientists and Belisarius Cawl extract your gene-seed for testing," Rhodes said.
"But there's a problem—if it works, you'd have to strengthen them with the old gene-seed first, then switch to the new super-evolved gene-seed.
But then the old gene-seed can't be produced anymore, and cultivating gene-seed is hard. The safest way is to let the Astartes themselves cultivate it—one every five years.
If everyone uses the super gene-seed, no one will produce the old kind," Guilliman said.
"So the old legions can't be abolished. If the experiment works, try it in small batches for now.
When the other mid-tier primarchs return, do it on a larger scale. New recruits can get the old gene-seed first.
Then after twenty or thirty years of service, they can switch. That should create a cycle," Rhodes said.
New recruits serve twenty to thirty years, producing five or six gene-seeds.
Then they can be upgraded, ensuring enough old gene-seed, and there's a gene-seed vault with plenty stored.
Even if no more were produced, the current stock would last a long time!
"Good plan. Let's return and report our victory to Father," Guilliman agreed.
This was a stable path: new recruits start with old seed, then upgrade after they mature.
…
After settling the gene-seed issue, Rhodes called Tartarus and teleported everyone back to Holy Terra.
By now, sixteen days had passed since they left.
The Mars rebellion had been crushed; over 70% of the Mechanicum was lost, and all rebels executed!
But the news was still sealed and hadn't spread to other worlds.
"You've returned? Looks like the plan was a great success—I can feel your strength has doubled," the Emperor said, very pleased.
Now the primarchs were just as he imagined—far superior to any other.
"Father, the task was completed smoothly. We also have a matter to report..." Guilliman explained the gene-seed evolution.
"No problem—your plan is the safest. Let Belisarius Cawl and the loyalist Mechanicum, along with Rhodes's scientists, extract your evolved gene-seed," the Emperor said.
The new Astartes were already strong; now the primarchs had evolved, and the gene-seed would be even more powerful!
After that, Guilliman asked about the Mechanicum.
"Father, what will you do about the Mechanicum?"
It was a huge issue: 70% had rebelled, all due to the Omnissiah. If the truth got out, a god worshipped by a quarter of the Imperium would be erased, causing chaos as bad as the Horus Heresy.
"I've considered that. I'll say Mars was hit by a meteor, killing many priests and Magi.
Those who survived will have their memories wiped, except for Cawl and Salome.
Then the Omnissiah's doctrine will be rewritten: the Omnissiah is only an avatar of the Emperor," the Emperor said.
The purge was secret; the Emperor had locked down communication. The Custodes and Dark Angels handled it with utmost secrecy.
So, with a little fabrication, the truth could be hidden, and the Omnissiah's doctrine gradually changed.
"This can be left to the Ecclesiarchy—they're experts at this. Say there was a meteor strike and Chaos incursion," Rhodes added.
If Logar were here, he'd handle it even better; he'd done religious purges before.
The Emperor nodded, agreeing that adding a Chaos incursion would make it more believable.
"The Ecclesiarchy doesn't need to know the truth—just have them preach to the forge worlds that the Omnissiah is the Emperor's avatar," Rhodes said.
The others nodded. These newly awakened primarchs didn't know much about the Imperial Creed—it seemed Logar's writings were not entirely without merit!
Soon, news spread across the Imperium: Mars was hit by a meteor and a Chaos incursion.
The Mechanicum headquarters suffered heavy casualties, over 70% lost, but the Imperium drove off the Chaos threat and saved Terra and Mars.