A dark, cold world──[Underworld].
It is an "afterlife" world composed of many layers, and the souls in each layer are assigned.
In the uppermost layer, you can feel the warmth of the earth, and this is where the souls of those who did good deeds during their lives rest peacefully.
Descending deeper from there, the lower level is an underground prison where the souls of those who had done evil in their lives are sent to.
"Ah…"
"G-get out…"
"It hurts… it hurts…"
The underworld, where the world itself is a prison.
The prison is made of special cages and bare rock surfaces that mercilessly harm the specters and souls housed there.
By nature, souls and specters do not exist as entities.
Therefore, a special power called [Mystical Power] or [Spiritual Power] was needed to harm them.
And in this underworld, everything is imbued with mystical and spiritual power to prevent them from escaping from their prisons.
In this underworld, where the screams of specters echo through the air, there is only one building.
In contrast to the dark and gloomy atmosphere of the underworld, the building is decorated with goldsmith's work and is extremely luxurious.
The floor is also covered with polished tiles, making it hard to believe that it is a building in the underworld.
In the center of the building, there is a hall where criminals are judged.
On an honorary seat, as if overlooking everything in the underworld, sat a young girl.
"I'm bored."
She was wearing a little civil official's hat on her bobbed hair, a royal scepter in her hand, and luxurious clothes that looked like some country's official uniform.
This girl was the king of the underworld──Reimei, and the master of this building. [T/n: Let me know if someone can provide a better name for this 霊冥, maybe Dark Soul?]
Reimei cheekily poked her head in boredom.
"The dead used to come here so often, but recently there have been fewer and fewer of them… Well, it means that time has moved on, and the world over there has become more peaceful, hasn't it?"
Reimei looked like a young girl, but her age was much older than anyone else in the underworld.
In ancient times, there were many conflicts in various parts of the world, and medical technology was not developed, so many people flowed into this underworld.
However, as time passed and technology developed, the number of souls flowing into the underworld at one time decreased, and eventually, Reimei's work also decreased.
"Well, peace is the best thing. There will be no major work for me to do today, so I will take a nap──"
"──Reimei-samaaaaaa!"
"….."
Just as Reimei jumped down from her chair, seemingly determined that today's work was done, a muscular creature burst into the building.
It was humanoid in appearance, with red skin and two large horns on its forehead, resembling the Bloody Ogre of the other world.
However, in its eyes, there was a light of reason that was different from that of a monster, and in addition, there was a sense of charm.
Suddenly, Reimei, who had been caught off guard, stared at the red oni with a blue vein on her forehead.
"What is it, Nikkaku? I'm just about to go to sleep──" [T/n: She called him Nikkaku or two horns (二角), should I just use the Japanese, or just translate his name?]
"This is not the time to say such a thing! T-the underworld is in trouble!"
"Huh?"
At the plea of the oni called Nikkaku, Reimei tilted her head and sat back in her chair again.
"What in the world is going on?"
"T-the specters of the underworld are escaping!"
"What?"
The report was unbelievable to Reimei.
"That is impossible! How is it possible for the specters in this land to escape from the underworld's prisons?"
"But, actually, the oni under my command are already working to capture the specters that have escaped from their prisons!"
"!?"
Reimei's mystical and spiritual powers created all the prisons that existed in this underworld, and there were no specters that were powerful enough to break through Reimei's mystical power except one.
"Don't tell me that Meiko's seal has been broken?"
"N-no, it seems that Meiko's seal is intact."
"What? Then why… in this current world, there should be no one but Meiko who can escape from my mystical power…"
As Reimei desperately pondered the cause, Nikkaku opened his mouth to say something that sounded difficult to say.
"Um, there's one more thing I'd like to tell you…"
"What is it?"
"The fact that specters have escaped alone is important, but the border between the underworld and that world seems to have disappeared…"
"Why didn't you tell me that first…?"
The content of what Nikkaku said was not something that could be left unattended.
Essentially, there is a firm boundary between this world and the underworld, and it is because of this boundary that those in the world of the living are not able to wander into the underworld.
Conversely, specters could not escape from the underworld into the world of the living.
But now that the boundary between the underworld and the living world has disappeared, specters who have escaped from their prisons in the underworld can easily escape to the world of the living.
"This is not good… If this continues, specters from the underworld will be unleashed in the world of the living…!"
For reasons unknown, now that the boundary between the world of the living and the underworld has disappeared, Reimei herself will have to take action.
"Nikkaku! Now mobilize all the other oni to guard the boundary between the underworld and the living world! I will reinforce the prisons and seal the specters again as soon as possible!"
"Y-yes!"
After receiving the instructions, Nikkaku ran out of the building, and Reimei got out of her chair and stood in the center of the room.
And then──.
"Hmph!"
At that moment, a torrent of purple power, cloaked in a bewitching atmosphere, overflows from the center of Reimei, and the wave blows across the entire underworld.
At the same time, the prisons of the specters who were about to escape were once again strengthened by the solid mystical and spiritual power, making it impossible for the specters to escape.
"Phew… this should be enough to strengthen the prison for the time being."
Once again, Reimei spread her own mystical power throughout the underworld, and after confirming the situation of the underworld, she let out a deep sigh.
"…I never thought that the prison seal would be broken and the boundary between the world of the living and the underworld would disappear…"
With the unprecedented emergency situation in the underworld, Reimei shook her head with a grim expression on her face.
"No, let's think about the cause later. I must seal them back up before any more specters escape from their prisons and flee to this world──Fuh!"
Then, purple power erupted again from under Reimei's feet, and it transformed into countless giant 'hands.'
In the next instant, countless purple giant hands ran all over the underworld at once, seizing fleeing specters and sealing them back into their prisons.
After sealing all the specters in their prisons, Reimei let out a small breath.
"Nikkaku, Ikkaku."
"──Yes!"
"Did you call for me?"
At Reimei's call, Nikkaku and the blue-skinned oni known as Ikkaku appeared and kneeled there without a sound.
"Nikkaku. Have some of the oni guard the perimeter, and gather the rest of the oni in this hall."
"As you wish!"
"Ikkaku, while the oni are gathering, investigate the cause of this disturbance."
"Understood."
Both oni immediately disappeared from the scene, and a few moments later, Nikkaku gathered all the available oni under his command, just as Reimei had ordered.
Then, Reimei looked around at the assembled oni and began to speak in an imposing tone.
"───Thank you, all of you, for gathering here. There is an emergency in the underworld. As you all know, the boundary between the underworld and the living world has disappeared, and specters have escaped into the living world. I immediately resealed the prison and was able to seal the escaped specters before they headed to the living world, but it is a fact that some of them have managed to escape. And now that the boundary has disappeared, it has become necessary to be vigilant to prevent those from the living world from wandering into this one. Of course, I am still working to repair the boundary, but a complete repair will not be a quick process."
After sealing the specters that escaped from the prison, Reimei had also begun to reconstruct the boundary with her own mystical power.
However, reconstructing the boundary between the living world and the underworld is different from reinforcing the prison of the underworld, and it will not be an easy task.
"Therefore, everyone should be more vigilant and watch the boundary between the living world and the underworld than ever before!"
"Understood!"
"And, Ikkaku! What have you found out?"
When Reimei finished giving instructions to the oni, Ikkaku appeared from among the group.
"Yes. The cause of this incident was a single soul that flowed into the underworld."
"What do you mean?"
Reimei tilted her head at Ikkaku's words.
This is because Reimei had assumed that the specters in the prison had cooperated with each other to escape from the prison and, at the same time, had somehow worked out the boundary with the living world.
In reality, however, Reimei was surprised to find that the cause was a single soul that had drifted into the underworld… that is, a soul before it had been judged by Reimei.
"What in the world is going on?"
"Actually, that soul that drifted into the underworld… belonged to a false god."
"False god?"
When Reimei twisted her head in response to the unfamiliar word, Ikkaku explained.
"The 'false god' is a kind of disaster that appears in the [Heavenly Realm] where the gods live. Their power is such that they annihilate everything they touch, and to counteract them, one must have a power called divine authority."
"I know about divine authority. The power of these observers is the very embodiment of omniscience and omnipotence. But still, who would have thought that there is an existence that cannot be defeated without such power?"
Reimei also knew of the existence of the heavenly realms, but since the observers living in the heavenly realms have no concept of life or death, and the only threat to their existence is annihilation by the false gods, thus their souls have never been able to flow into the underworld.
"So what? What does this false god have to do with this case?"
"As I mentioned earlier, the false god has the power to annihilate everything it touches. That does not change, even if he is only a soul. In other words, anything that touches the soul of the false god will also be annihilated."
"What? No way…"
"…This time, his soul touched the boundary between the living world and the underworld, and that boundary disappeared."
If Ikkaku's story is true, the soul of the false god could erase any boundary or, worse, even the concept of existence in it just by its presence, and if left unchecked, the underworld would surely be in turmoil.
"Where is that soul now?"
"Fortunately, the soul of the false god was already weakened by the time it arrived in the underworld, and its spontaneous extinction has just been confirmed."
"Oh…"
Once it was clear that the damage would not spread any further, Reimei leaned back deeply in her chair with relief.
"W-what a troublesome existence…"
Reimei was left scratching her head, wondering why this had happened!