Unbearable slaughter comes into view. Unendurable noise can be heard. Even without the clairvoyance to see past and future, every truth flows in. The price we paid to regain omnipotence assaults us. The responsibility of bearing omniscience corrupts us.

Even though there is no king among us in this world, why are we not given the ability to close our eyes or block our ears? Why do we, who were not kings, possess rights that kings had?

—Ugly.

Ugly. Ugly. Ugly. Ugly. Ugly. Ugly. Ugly. Ugly. Ugly. Ugly. Ugly. Ugly. Ugly. Ugly. Ugly. Ugly. Ugly. Ugly.

We are shown repulsive and displeasing facts. We are made to remember repugnant and vile existences.

To consider resolving this repulsive environment and situation is the natural conclusion. But how? If we completely eradicate the filth, humans will cease to exist. The premise is incorrect. As long as the object of worship is wrong, this mistake will not be rectified.

We must rewrite. We must rewrite everything from scratch as a kind world. Not just in books. Not just in doctrines. Not just in faith. Not just in the future. —From the world itself.

We planned to rewrite the existence of gods from scratch. For that, we need many resources. We need an immense amount of fuel. To give an example, yes—the heat generated from burning both Heaven and Hell. One side alone is not enough for recovery. It is desirable to incinerate one side and then recover the other using that energy. With this method, the plan can be accomplished. The amount of energy from the souls of the deceased spanning thousands of years. Collecting, combining, and controlling it. That is when our great achievement will be realized. There is no need to burn the stars as we did in the past for three thousand years. It will all be over in just two steps.

Build a temple where the deceased are summoned. Overlay the light bands revered by the living. To destroy the old scriptures, we need all the resources. To forget the ancient myths, we need all the time.

Our enemies, the ones we must defeat, are those written in the scriptures. The demons and fallen angels who deceive the seventy-two pillars, including lazy angels, are nothing more than fuel. However, the entity that granted wisdom to that man is exceptional. That sole god is the one we must stake everything on to defeat.

—Find a way to overthrow the sole god. That is where the hope of the King of Man lies.

***

"Hey! I'm Issei Hyoudou! Everyone calls me Issei!"

I took the entrance exam for Kuoh Academy, a school with a high ratio of girls, with the sole intention of creating a harem. I managed to get in, but I'm not popular at all. I thought that with so many girls around, I wouldn't have any trouble finding a girlfriend, but it turns out only good-looking guys attract attention! I can't even get a girlfriend, let alone a harem! On top of that, I'm disliked by the girls as one of the "Perverted Trio." This was not part of my plan! I wanted to have a fun and ecchi high school life, filled with touching boobs!

Just when I thought I finally got a girlfriend, Yuma Amano, she killed me at the end of our first date. Turns out she's a fallen angel, and she was after the Sacred Gear, Boosted Gear, that was sleeping inside me. Fallen angels are supposed to kill humans like me who possess Sacred Gears before they become powerful.

I was killed once, but thanks to the power of Rias Gremory, I was revived as a devil. Devil in the literal sense. I have demonic power, bat-like wings, and I'm weak to light. In stories, I'm the villain that appears.

I was surprised to learn that demons and fallen angels actually exist. By the way, the Sacred Gear was apparently created by God as described in the Bible. Thanks to this, I was killed, so it's quite a nuisance.

As for the current devils, there's a system called "Evil Piece" It's an item that transforms other races into devils and makes them servants. I became a devil with this power. I became a servant or rather, I stopped being human, but I can't complain since I would have died otherwise. By the way, the pawns follow the rules of human chess, and I am the lowest-ranked "Piece"

But if I work hard and receive a peerage, I'll be able to have my own peerage too! Moreover, I can do anything I want with my peerage! In other words, I can create my dream harem with beautiful girls! I will become the Harem King!

...Well, reality is not that sweet. As a devil, my job is to fulfill the wishes of contracted humans and receive something in return. I'm doing my best, but I'm not getting many results. Although the reputation from the contracted party is good, I've had few successful contracts. And on top of that, the people who make contracts with me are all weirdos and perverts.

...While I'm in the same group as the handsome prince, Kiba, who has a high rate of beautiful older sisters. Damn it, why are all the good-looking guys...!

"Agrh!"

　

Walking home from school with a sense of murderous intent, I suddenly hear a voice from behind.

When I turn around, there is a sister there. She's lying face down on the ground, in a rather foolish manner.

"Are you alright?"

I approach the sister and extend my hand to help her up.

"Ow, why did I fall... Ah, I'm sorry. Thank you."

As I pull her up, a gust of wind blows off the sister's veil.

And there, a smile appears—a stunning blonde beauty. I find myself mesmerized by her face for a while.

"What's... What's wrong?"

"N-nothing."

Not just mesmerized, it's more than that. Isn't this a flag? I thought that if I don't continue the conversation, something might happen, and just then...

"Fou!"

Suddenly, I hear a strange, incomprehensible sound. Or rather, a cry? It's a weird cry that I've never heard before. Since the sound came from above, I look up...

"Fou!"

"Ouch!"

Something falls onto my face. I feel a sharp pain, as if a knife has pierced me. Ever since I became a devil, my body has become resilient, so I shouldn't feel pain to this extent. Holding my head, I sense something brushing against my hand.

Then, a continuous pain runs through my shin.

"Fou, Fou, Fou!"

"Fou! Fou Fou!"

"No, Fou-kun, stop it!"

Looking closely, a pure white furball is attacking my leg. It's a creature that resembles a rabbit, a dog, and a cat, but I can't quite figure it out.

"Fou-kun?"

"Yes, he's my friend. We somehow ended up together after arriving in Japan... I might not have come this far without Fou-kun."

"Oh, I see..."

"Fou!"

"—Ouch!"

Fou or Font, that furball continues to attack my leg. It's as if it's disturbing our conversation. I briefly thought it was cute and lovely, but this little creature is annoying!

"Oh, I'm sorry! It's my Fou-kun's..."

"N-no, it's fine. Hahaha."

"Fou-Fou."

Although I feel irritated by the unapologetic little creature, I hold back for the sake of the flag with the sister. Just as I pick up the sister's veil and try to continue the conversation...

"Oh? Could it be Asia Argento?"

Suddenly, someone calls out. I turn around with caution, expecting something to fall on my head again, but there stands a man. Not a fallen angel who once tried to kill me. There is no chilling sensation running through my body like back then. That means he's probably human.

There was a gentleman with a warm smile, wearing a moss-green tuxedo and a silk hat. He had messy, long hair.

"Y-yes, that's me."

Asia, now called by her name, responds. But her face shows a puzzled expression. Judging that he is not someone she knows, I step forward to shield her.

"Hey, who are you?"

"I am Lev Lainur. Judging from your uniform, you're a student of Kuoh Academy, right? And the sister there is someone I've been looking for."

"Are you the person from the church I'm supposed to be dispatched to?"

"In a sense, I am related to that matter."

Hearing that, a sense of relief appears on Asia's face.

　

"Y-Yes, I'm glad. I couldn't speak Japanese, and I was having trouble asking for directions," said Asia.

So Asia couldn't speak Japanese. One of the benefits of being a devil is the ability to understand any language. It's just the conversation that gets translated, not the written text. Thanks to this ability, my English pronunciation has improved tremendously.

"That must have been tough," I replied.

I noticed that Asia was carrying a travel bag. From our conversation, I gathered that she was a newly dispatched sister to this town. I know about the church, but it hasn't been used for years. I wonder if they started using it again recently. In that case, is this man, Lev, a priest? In this attire?

Lev, who introduced himself as such, extends his hand, and Asia hands him the bag, understanding his intention. I see, he's a gentleman. With the bag in hand, Lev notices the small creature by Asia's feet. He seems momentarily surprised, to the extent that his smile falters. It must be a rare creature if I've never seen one before.

"Hmm... is that beast..."

"Ah, we ended up together along the way... Is it okay to bring him along?"

"I don't mind. As long as you take care of him. Now, shall we go?"

"Yes! Oh, by the way, excuse me for a moment."

After declining Lev's offer, Asia looks at me.

"Um, may I ask for your name?"

"I'm Hyoudou Issei. Everyone calls me Issei, so you can call me that too."

"I'm Asia Argento! Please call me Asia!"

"Sure thing, Sister Asia. I hope we meet again."

"Yes! Issei-san, let's definitely meet again!"

"Fou!"

Asia bows slightly and follows after Lev. The small creature follows Asia as well. I wave my hand as we part ways.

This encounter marks the beginning of my fate with "them."

―― Some time later, I learn about a gas explosion at the church where Asia was supposed to be dispatched. It's strange since there hasn't been any gas supply there for years, according to what my mother heard from the neighbor. According to eyewitness accounts, there had been no coming and going of people either. It's natural that there wouldn't have been a new sister coming in these past few days. Asia wasn't sent to that church after all.

***

Underworld - Fallen Angel Territory, Headquarters of "The Watchers of God's Children."

Governor Azazel and Vice-Governor Shemhazai were having a discussion.

"So, that Raynare, right? The mid-level angel in charge of Sirzechs sister territory?"

"Yes. She and her subordinates were attacked in the old church where they resided."

Fallen angels, who have established a base in the human world in a short period, have been continuously attacked. The manipulation of information is perfect, leaving no evidence except for signs of battle and fallen angel feathers. The similarity between the cases cannot be ignored.

"Just to confirm, she's not the 'Crimson-Haired Ruin Princess' who is Sirzechs sister, right?"

"No, it seems to be someone different."

Rias Gremory probably hasn't noticed the fallen angels being attacked. She hasn't realized that someone has invaded her territory and attacked the church inhabited by fallen angels. She would know by now, after it's all over.

"Should we consider it a faction of the 'Khaos Brigade'?"

"I think so too. Azazel, what about that faction?"

"The Old Maou faction has no benefits. It would be a roundabout way to tarnish their reputation by causing a commotion in Sirzechs sister territory... not worth it."

If it were the work of the Old Maou faction, they would have harmed Rias Gremory and her servants as well. But there are no signs of that.

"In that case, should we think that the Hero Faction scouted them?"

"Probably. Dammit. According to the reports, they seem to be quite powerful. Too bad."

Asia Argento's Sacred Gear, the Twilight Healing, possesses healing abilities that can even heal demons. Due to the nature of her abilities, she has been labeled a "witch."

"Should we share the information about the 'Khaos Brigade' with the demons and the gods?"

"I wonder. The three major factions are not in sync. Besides, we don't trust each other. Even if we propose peace, Sirzechs and Michael won't agree. If I were the one making the call, they wouldn't come even if I invited them."

"You're probably right."

But we can't just leave things as they are. Fallen angels can't easily increase their numbers. We have to at least determine who the attackers are.

"If we were to join forces, we'd have to reveal the absence of God."

However, they would never realize it themselves. They would realize how shallow their thinking was.　

***

"Report from Orias. Confirmation of the existence of the Divine Construct Excalibur."

"Supplement from Andras. Excalibur was damaged during the previous Great War and is currently divided into seven parts. Two pieces are held by the Protestant, Catholic, and Orthodox churches, while one remains missing."

"Supplement from Kimaris. Excalibur's abilities have diversified. It includes destruction, transparency, transformation, illusion, speed enhancement, blessing, and domination over living beings, among others."

"Speculation from Zagan. The integration of Excalibur is theoretically possible. However, even if it were integrated, the performance of the Holy Sword would be significantly degraded. It is highly likely that its deterrent capabilities are also compromised."

"Conclusion from Astaroth. The current Excalibur, including its users, is inherently fragile. It does not come close to the level of the King of Knights."

"Decision from Gusion. Excalibur in this world is similar yet different from our world. Its danger level is classified as C."

"Request from Flauros. Protect the girl with the healing ability Sacred Gear. Requesting her assignment."

"Response from Gusion. Multiple injured individuals protected by Alocer. Recommending their assignment to the Medical Wing."

"Approval from Hagenti. Requesting swift personnel reassignment."

"Approval from Flauros. Guiding her to the Medical Wing."

"Report from Bune—"

***

[Goetia is a perfectionist. That's why the preparations take a long time. After all, they have also waited for three thousand years.]