Devas.
This is a sub-divine race referred to as ancient superhumans and ancient gods.
There exists a world where, in addition to humans, many other races have survived and thrived since ancient times.
Beastmen, elves, half-demons, artificial lifeforms, vampires, succubi, atmospheric spirits, giants, and even dragons... In this world, many non-human lifeforms coexist with humans.
Among them, all non-human races are collectively referred to as demons—except for the Devas.
They are a species that surpasses humans, a civilization that constructed a highly advanced society in prehistoric times, created all kinds of powerful weapons, regarded humans as an inferior race, and treated war as entertainment, manipulating humans into killing each other.
And Leviathan had already existed on the surface before the emergence of the Devas—it was the strongest biological weapon of the mythological era, a prehistoric magic beast that had drifted near dragon veins and slept quietly under the sea for thousands of years.
Although a magic beast, Leviathan was an artificially created weapon. Its body not only contained numerous installed weapons, but its internal structure resembled a chamber that people could enter and move about in. To call it a living super aircraft carrier would not be an exaggeration.
In other words, Leviathan was both a living creature and an armament—a weapon that could be wielded.
"So, this is the reward I received this time?"
Kaiser finally understood what kind of thing his reward this time was.
Leviathan, also translated as Levia-tan, means "fissure," and in the Bible it is a sea monster that symbolizes evil.
In Christianity, Leviathan once became synonymous with the devil and was associated with one of the Seven Deadly Sins: Envy. That's why, in the High School DxD World, one of the Four Great Satans bears the name Leviathan. Devils who inherit this name are either Satans or direct descendants of Satans.
But in that world, Leviathan refers to this strongest biological weapon from the mythological era—a prehistoric monster that has survived to the present and is considered the most dangerous magic beast.
Its power is enough to rival that of the True Ancestors of vampires.
Its history surpasses even that of the Devas.
"I didn't expect that the reward this time would actually be it."
This was undoubtedly a weapon of war more terrifying than nuclear weapons—perhaps not even inferior to Typhon, the strongest monster Kaiser had summoned using his Authority.
In other words, if this were placed in the world of the Campione, it would absolutely be a weapon capable of God-Slaying!
"If it recognizes me as its master under the effect of my Authority, it can become even stronger."
At that thought, the surprise on Kaiser's face finally turned into a smile.
As long as he used his Authority to forge a master-servant bond with Leviathan, making it his exclusive weapon, it would be enhanced.
Moreover, since Leviathan was both a weapon and a living creature, if he used the Authority of the King of Monsters, he could perform a secondary enhancement.
This much could already be seen from how Kaiser had just used the Authority of the King of Monsters to successfully control Leviathan.
By that time, this mighty prehistoric weapon could very well become one of his trump cards.
"Buzz!"
Kaiser immediately activated his Authority, causing golden embossing-like patterns to appear and spread toward the gigantic beast before him.
Under the inscription of the golden patterns, the ultramarine circuits on Leviathan's body were instantly replaced by dazzling gold, becoming noble golden circuits.
"■■■■■■■■■■■■■■——!!!"
When Leviathan once again let out a storm-like terrifying roar, the circuits on its body had already turned completely gold, and the aura and pressure it emitted had increased severalfold—far more terrifying than when it first appeared.
With Kaiser's current strength, the degree of enhancement brought about by his Authority upon bonding with an exclusive weapon was far greater than before.
"Clang——"
At the same time, the book that had flown to Kaiser's side resonated with Leviathan, causing fluctuating light to appear on both of them.
[Open the book to enter the fantasy world recorded within, and perform a randomized extraction of a life experience.]
[Note: The Librarian holds a key component of the fantasy world recorded in the book. If the book is opened while holding this element, the range of the extracted life experience will be narrowed, yielding a background more closely related to that element.]
[The Librarian may also store away the key component of the fantasy world recorded in the book. If done so before opening, the extraction will proceed randomly without narrowing.]
The will of the Fantasy Library descended, causing Kaiser to shift his gaze from Leviathan to the book glowing flickeringly before him.
"Looks like the world I'm descending into this time is that one..."
Kaiser, already aware in his heart, pondered for a moment. Then he reached out and opened the book before him, causing its pages to automatically flip, separating one by one and fluttering around him.
"■■■■■■■■■■■■■■——!!!"
Leviathan let out another roar, and the flickering light on its body began to resonate with the pages floating around Kaiser.
This time, Kaiser did not put away Leviathan.
"In the past few experiences, the starting backgrounds were all apocalyptic. This time I want to see what kind of background I'll get if I don't store away Leviathan."
With that thought, Kaiser allowed the pages fluttering around him to be gradually reduced under Leviathan's fluctuating glow.
Eventually, only one page remained around Kaiser, and the cover of the book before him displayed a title—Strike the Blood.
"Whoosh!"
The last remaining life experience page flew into Kaiser's mind, causing him to close his eyes and merge with that blank book, and together with Leviathan at his side, disappear from where he stood.
"Rumble rumble..."
At this moment, the Fantasy Library, which had previously expanded to a vast extent, slowly began to tremble and shrink, returning to its original state.
The starry river in the sky still flowed, and the fountain in the courtyard still gurgled. The scene remained unchanged for a hundred years, as if it would never alter...
......
By now, Kaiser was already used to the sensation of entering a fantasy world.
Whether it was the initial spinning of the heavens and earth or the feeling of firmly stepping on solid ground that followed, it was all so familiar, so real.
However, this time, before Kaiser even opened his eyes and set foot on solid ground, a segment of memory first appeared in his mind, which he began to absorb.
It was the memory belonging to the background of this life experience.
Unlike before, this time, Kaiser's life background seemed to be somewhat complicated, somewhat special.
In the memory, he saw himself sleeping inside a giant beast.
The beast looked like a draconic fish; its fins shimmered with iridescence, its scales were ultramarine, and its size was as vast as an island. Even slight movements in the sea caused surging currents and powerful turbulence.
It slept year after year, day after day, paying no attention to aircraft carriers or nuclear submarines, slumbering for millennia beneath the sea.
As long as nothing approached it near the dragon vein, it would not respond.
As long as no one tried to attack it, it would remain indifferent.
Hundreds, thousands, tens of thousands of years... it had always been like this.
And the boy sleeping within it—who appeared to be only twelve or thirteen years old—slept just as it did, day after day, year after year, never waking.
Until one day, an immense surge of magical power suddenly appeared in a corner of the Far East seas, interfering with the flow of the dragon vein and awakening the beast.
Drawn unconsciously by this magic, the beast swam toward it and appeared in that part of the Far Eastern sea.
The source of the immense magic seemed to come from an island—an artificial island.
The appearance of this magical power seemed to be due to an accident—an accident that was never meant to happen.
Because of it, the beast appeared, startling the entire world.
Yet, the beast did not rampage on the artificial island. Instead, it suddenly turned into light and merged into the body of the sleeping boy within it.
Because of this, the boy appeared in the world for the first time and was taken in at the coast by a special agency of the Far Eastern island nation, Japan.
This special agency was a governmental department established under the National Public Safety Commission, tracing back to the Takiguchi Musha of the Heian era who protected the palace from evil spirits and demons. It handled large-scale man-made magical disasters and intelligence work. It also hosted and protected important international figures while monitoring them.
Its name was the Lion King Organization, headquartered on the japan's mainland, with sub-agencies including the Bureau of Magic Disaster Management and the training institution High God's Forest.
The boy taken in by this organization was given the codename—Chaos Dragon.
That is the essence of Leviathan in the Old Testament. Before becoming a demon, it was a Chaos Dragon—reputedly the largest creature created by God Yahweh and a magic beast capable of destroying the world.
Upon evaluation, the boy was determined to be the control terminal created in the mythological era to command Leviathan—its core, as well as the sacrificial vessel used to seal it.
Ultimately, by the unanimous decision of the three leaders of the Lion King Organization, the boy was placed in High God's Forest to be monitored and educated by the organization.
This was the memory of the life background that Kaiser received.
"A control terminal and sacrificial vessel for sealing..."
Kaiser's lips twitched slightly as he opened his eyes, unable to speak for a long time.
"This beginning... is it good or bad?"
Even Kaiser didn't know how to evaluate it.
Call it good? It sounded kind of miserable.
Call it bad? Compared to the previous ones, it seemed rather unique.
What left Kaiser speechless the most—was that he had become someone nurtured, educated, and monitored by the Lion King Organization.
And what was the Lion King Organization?
That was a matchmaking agency nicknamed the Red Thread Organization!
So in other words...
"Good grief, the one being matched for marriage is actually me?"
Moreover, what kind of operation was it to throw him into High God's Forest?
Isn't that an all-girls boarding school?!
(End of Chapter)