—"Longinus."
This is an existence born in a world where gods, angels, devils, fallen angels, dragons, and various mythologies coexist.
In that world, the god known as the "God of the Bible" created what are called Sacred Gears.
They are extraordinary powers residing within specific humans—unique artifacts with special abilities that evolve and grow stronger by feeding on the will of their owners.
Many individuals who have left their mark on history or are prominent athletes often possess these abilities, though they themselves remain unaware. Only under certain conditions and with specific capabilities can these powers be fully manifested.
Most Sacred Gears have effects that, at most, influence human society. However, there exist a rare few that possess power capable of threatening devils and fallen angels.
Among them, an even rarer category of Sacred Gears exists—those with the power to threaten gods and even Maous.
These are the Longinus, the highest-tier Sacred Gears.
The True Longinus is one such Longinus.
It is the holy relic from myth, the very spear that pierced the Son of God and took His life.
This relic is the first Longinus, as well as the strongest.
There exists no Sacred Gear more powerful than this spear, nor anything holier.
Thus, it is a weapon capable of piercing gods and, at the same time, the most effective counter against devils. Whether against gods or Maous, it poses a genuine threat, making it one of the most coveted and feared Sacred Gears across all factions.
And now, this Sacred Gear had become Kaiser's reward for completing his first Life Experience, falling into his hands.
"So… I've become the wielder of the strongest Longinus?"
Kaiser held the True Longinus, feeling somewhat dazed.
Yet, as he stood there in confusion, the will of the Fantasy Library once again descended.
[Librarian has completed their first Life Experience, meeting the conditions to acquire an Inherent Authority.]
[Commencing authority grant…]
Inside the Fantasy Library, the glowing books brightened further, forming a dazzling radiance that enveloped Kaiser.
"A new authority…?!"
Kaiser reacted immediately, his expression a mix of shock and delight.
But then, he noticed something unusual.
"What exactly is Inherent Authority?"
With this question in mind, Kaiser closed his eyes, bathing in the light, allowing it to infuse his body and form new power within him.
Before long, the radiance faded, and the newly granted Authority took shape.
Kaiser opened his eyes, a look of realization flashing through them.
"So that's what it means…"
He now understood what Inherent Authority was.
As the name implies, it is a fixed Authority.
Unlike the previous Authority he had obtained, this Authority is something that all librarians who complete their first Life Experience receive.
When an librarian first enters the Fantasy Library, they are granted a Authority—one that is uniquely suited to them, formed based on their own conditions. It is one-of-a-kind, and no second person will ever obtain the same one.
However, the Inherent Authority is different—it is a standard authority granted to all librarians upon completing their first Life Experience, with a simple yet significant function: converting one's Power System.
Since every Fantasy World has different Power Systems, the Inherent Authority was created to prevent contradictions between these systems from affecting an librarian's strength or Life Experience. It allows librarians to freely switch between different Power Systems when entering a Fantasy World.
The more Fantasy Worlds an librarian has experienced, the more Power Systems they can convert between. Furthermore, once converted, an librarian can revert back at any time without affecting their original strength.
Additionally, when switching Power Systems, both power level and proficiency remain exactly the same, ensuring that the librarian does not feel unfamiliar or unable to fully utilize their abilities.
The only aspect that does not change is physical strength.
Regardless of the Power System, an librarian's physical strength remains unaffected and does not conflict with the world's rules.
Thus, only the Power System undergoes conversion—the body itself remains unchanged.
"Now this is an interesting Authority."
Kaiser found it intriguing, though he also felt a bit disappointed.
While this Authority was certainly useful, its impact on his strength wasn't as immediately significant as a Unique Authority.
"Fortunately, I still have this."
He turned his attention back to the True Longinus in his hands.
The Authority within him told him that this spear held immense power.
Power far beyond that of Ser-Veresta or Gravisheath.
A power capable of threatening both gods and Maous.
Compared to this, the so-called Orga Lux was simply insignificant.
In that world, weapons like Ser-Veresta and Gravisheath, despite being Orga Lux, were at best equivalent to ordinary Sacred Gears. While significantly stronger than those that merely affected human society, they were nowhere near the level of a Longinus.
However, the True Longinus was not just a Longinus—it was the strongest one, standing in a league of its own.
If he could fully master the power within this spear, his strength would undergo a complete transformation.
At the very least, wielding the True Longinus in the Asterisk War world would be absolute overkill. The so-called monsters of Jie Long Seventh Institute and Le Wolfe Black Institute would be nothing more than child's play.
Such power, in anyone else's hands, might require a long period of training and refinement to unleash its full potential.
But for Kaiser, who possessed Ultimate Authority Over Weapons, the moment he grasped the spear, he had already mastered its power!
And that power would only continue to grow!
"Zing!"
Golden engravings emerged on Kaiser's hand as he gripped the True Longinus.
These golden patterns extended from his palm to the spear itself, spreading along the shaft and reaching the luminous spearhead, covering its entire surface.
Like Ser-Veresta and Gravisheath, the True Longinus had its own will.
However, when the golden patterns enveloped it, the True Longinus did not resist—its will did not even attempt to surface, directly acknowledging Kaiser as its master.
Thus, the first and strongest Longinus became Kaiser's third Exclusive Weapon, merging completely with him.
Since Sacred Gears naturally integrate into their owners, and Kaiser's Exclusive Weapons are entirely one with him, he could clearly sense the will of the True Longinus.
It was unlike the wills of Ser-Veresta or Gravisheath.
This will was grand and sacred, as though a true divine presence resided within.
It did not display submission, fear, or reverence toward Kaiser—instead, it was curious, observant, and approving.
Of course, regardless of its attitude, it did not affect Kaiser's control over the spear.
He could wield the True Longinus with perfect mastery, its immense power entirely at his command.
"Looking forward to working with you."
Kaiser lifted the True Longinus and smiled.
A radiant glow flickered across the spear, as if in response.
Then—
"Whoosh!"
A book suddenly flew in front of Kaiser, its surface shimmering with an ethereal glow.
"Hmm…?"
The True Longinus reacted to the book, trembling slightly as it emitted a matching light.
The Fantasy Library's will descended once more.
[Opening this book will allow the librarian to enter the Fantasy World recorded within and undergo a randomized Life Experience.]
[Because the librarian possesses an important element of this Fantasy World, opening the book will narrow the selection to experiences closely related to that element.]
Kaiser took in the message, looking at the book in front of him with intrigue.
"Could it be…?"
As a certain thought crossed his mind, Kaiser hesitated for a moment before reaching out and flipping open the book.
The cover revealed itself, displaying its title—
"High School DxD."
"As expected, it's this world."
With a knowing smile, Kaiser stepped forward and touched the book—
Entering its world…