Osiris had once descended as a Heretic God from the Realm of the Dead.
The one who summoned him back then was none other than Marquis Voban, one of the current Campiones on Earth.
The Authority he usurped from Osiris was called [Cage of the Servants of Death].
[Cage of the Servants of Death]
Description: Those personally slain by the user—humans, divine beasts, demons, or artificial beings with souls—can be preserved in the world as living corpses (undead) and become absolutely loyal servants who obey without question.
These servants, whose souls are imprisoned by the Authority, can regenerate even if their bodies are destroyed after a short time.
Additionally, aside from divine beasts whose souls are too massive to move instantly, all other servants of death can appear at the user's side from anywhere in the world with a single thought.
In Damien's opinion, the Authority was actually quite convenient.
If he brought it back to the Central Continent, he could hand it over to Diablo and the others to build a massive undead army.
"It would be nice to obtain something similar."
Damien craved the root power of the Egyptian mythological system, but he was equally interested in unique Authorities like this one.
He planned to summon two Heretic Gods.
The first was Osiris, god of the underworld and fertility, from whom he intended to claim an Authority capable of establishing a true netherworld.
The second would be a major deity of sufficient weight in Egyptian myth so he could plunder the entire Egyptian pantheon through him.
"Viel."
Damien asked, "Can you raise the upper limit of this Authority based on the Cage of Dead Servants?"
"Theoretically, yes."
Viel answered, "If you infuse enough ultimate power into it, even the most ordinary skill can be elevated to an extraordinary level."
In other words, the upper limit of the Campione-world version was divine beasts.
In Damien's hands, it could become a true Cage of the Dead.
At its core, the skill was simply soul binding and physical regeneration.
Similar abilities weren't rare on the Central Continent.
Compared to Rimuru's devouring evolution or Velgrynd's demotion absorption, soul restraint wasn't particularly advanced.
"I already have the Wheel of the King of Hope and Luminas's life-and-death control from the King of Lust."
With a solid template as a foundation, Damien was confident he could create a genuine afterlife realm on the Central Continent.
The Greek underworld was decent, but Greek myth didn't suit the concept of reincarnation well.
Greek legends rarely mentioned the next life or reincarnation; they were more like resting places for heroic spirits.
"Still, the underworld can serve as a reference. I'll incorporate it too."
That way he would never have to worry about the lifespan of the Monster Kingdom's citizens again.
Death would only be the beginning.
They could ascend as valkyries, become long-lived elves, preserve their souls eternally, or even reincarnate within the nation itself.
Whatever other mythologies had, Damien would have.
Whatever they lacked, Damien would create.
"The Egyptian pantheon's power will satisfy you."
According to Viel's calculations, Egyptian mythology had studied the afterlife and the world of the dead more thoroughly than any other system.
At the same time, after forming a divine contract with Damien, Set finally emerged from the Netherworld.
A divine contract was a special pact similar to an oath, mediated by divinity.
If either party violated the terms, they would suffer divine retribution.
Breaking it lightly caused severe injury; in severe cases, the divinity itself would shatter, leading to a demotion of myth.
Of course, such oaths had little effect on Campiones.
Still, they were normally used between gods.
A clause like "you can never trouble Set again" was mostly for show and unlikely to bind anyone.
Fortunately, Set hadn't asked for anything too extreme.
As long as the oath restricted Damien for a few days, Set was satisfied.
As for what happened after that…
Set didn't care.
A few days were more than enough for him to relocate his divine realm and never see these cursed stars again.
"God-slaying beast, are you truly challenging my kin?"
Set had more or less figured out the relationship between Damien and his two familiars. "They are your servants, aren't they?"
"A Campione must fight a fair battle to obtain a new Authority."
Although the original story rarely showed Campiones dying at the hands of Heretic Gods, that was only the anime's depiction.
In reality, every challenge carried considerable risk.
"That has nothing to do with you, Set."
Damien ignored him. "Don't worry, I won't break my word."
Since the god had helped, Damien had no problem letting him go.
Under Set's guidance, Damien skipped the usual requirements of a miko and believers.
He used the relic of Osiris's "little brother" as the medium and completed the summoning ritual for the Heretic God with crisp efficiency.
"Who dares?"
"Who dares desecrate my sacred relic?!"
The furious roar seemed to rise from deep underground. The entire desert trembled.
The gates of the underworld slowly opened. An icy wind seeped through the cracks, swirling the dust on the ground into ghostly dances.
Osiris, king of the underworld, stood clad in a black robe. He appeared to be in his forties or fifties, with a beard, a crown upon his head, and holding a crook, flail, and the scepter that symbolized supreme authority.
He stood atop a staircase built from countless stone tablets, each engraved with the names of underworld judges.
"Osiris…"
Seeing his old enemy again, Set couldn't help but murmur the name.
"Set!"
Osiris looked down. He saw Set—and the canopic jar in his hand.
It was the one part of Osiris's body that Set had sealed away—the male organ, the sacred relic Isis had never recovered.
"Return it to me!!"
Osiris, freshly descended and not yet fully adapted to his state, raised the ankh—the symbol of life and resurrection from the cards of the dead—in fury.
In an instant, boundless darkness engulfed the oasis where Damien and Set stood.