While we stood there, reeling from the sheer insignificance of the Demon King’s invasion, Lilia’s expression turned solemn. She pointed toward a black mark on the bottom-left corner of the map and continued.
“It might have been different in the Demon Realm, where absolute powers like the Six Kings reside, but to the Human Realm of that era, the sudden appearance of demons was a terrifying threat. The Demon King Army seized the surrounding nations in the blink of an eye. Their leader declared himself the Demon King and declared war on all of humankind. Thus began the long, grueling conflict between the two forces.”
“I should add that during the signing of the Friendship Treaty, the Underworld King offered a profound apology, stating that they should have properly finished the matter themselves. Despite receiving the mercy of the benevolent Underworld King, that wretch committed such selfish acts and even forced the Underworld King to bow their head… Even now, a thousand years later, the Demon King’s outrages remain utterly unforgivable.”
“U-Um, Lunamaria?”
Lunamaria, who had chimed in to supplement Lilia’s explanation, no longer possessed her usual composure. Her words were laced with venom, and her face was twisted in a display of pure loathing that honestly intimidated me.
“In the first place, for the sublime Underworld King to have to apologize for a piece of trash… but that is exactly what makes them the Underworld King! To have the breadth of character to bow to inferior humans, the grace to admit fault… truly, that person is the King among—”
“Luna! Luna!”
“Ha!? M-My apologies.”
Lilia rebuked Lunamaria, who had clearly been triggered by the mention of her idol. Looking at our bewildered faces, Lilia let out a weary sigh.
“Luna met the Underworld King once in the past, and she has been a fanatical devotee ever since. All of you should be careful—if you carelessly bring up the Underworld King to her, she’ll talk your ear off for hours.”
“…If it were possible, I would have much preferred to serve the Underworld King instead of being an old maid like this…”
“…Luna, I am definitely going to hit you two or three times later.”
Lesson learned: never talk to Lunamaria about the Underworld King. Her eyes were genuinely terrifying just now. She was completely tripping out—the word ‘fanatic’ really was the only way to describe her.
Good grief, Lilia certainly has her hands full.
“Anyway, let us return to the topic. The Demon King Army’s invasion of the Human Realm… actually, this was something that troubled the Six Kings as well.”
“““Eh?”””
I couldn't immediately grasp what she meant. Based on what we’d heard, the Six Kings possessed enough power to crush the Demon King Army in an instant. So why were they troubled? Wait… something did feel a bit off. If the Six Kings were that powerful, why was a Hero even necessary?
“…As I mentioned, the Demon King Army was neither famous nor feared within the Demon Realm initially. Therefore, the news that they had invaded the Human Realm reached the Six Kings quite late. By the time they found out, the Six Kings could no longer simply eliminate the Demon King Army.”
“…I see. The price of their non-interference came back to haunt them.”
“Senpai, what do you mean by that?”
Aoi seemed to have caught on to Lilia’s point, but Hina and I were still in the dark. If the Six Kings could have ended it easily, there must have been some reason they couldn't intervene.
Hearing Hina’s question, Aoi turned to her.
“At the time, the Demon Realm didn't interfere with the Human Realm. That meant they had no channels for negotiation… no way to convey that they had no hostile intent.”
“Oh! I get it!”
“It seems Miyama-san has realized it as well. That is likely the case. While most demons knew of humankind, very few had ever seen one. Conversely, the same was true for humans. To the people of that era, ‘demons’ were synonymous with the ‘Demon King Army.’”
Finally, the pieces clicked into place. Even if the Six Kings had the power to defeat the Demon King, they had no way to prove to the humans that they weren't also enemies.
If the Six Kings had swooped in and annihilated the Demon King Army in the blink of an eye, what would the humans have thought? The answer was simple: they would have seen it as the arrival of demons far more powerful and dangerous than the ones they were already fighting.
“A threat that far surpassed the Demon King. Humankind would have fought with the desperation of the doomed. If that had happened, it would have escalated far beyond a simple invasion. It would have meant total war between the Demon Realm and the Human Realm. No, even worse—if the Six Kings, the pinnacle of the Demon Realm, became involved, the God Realm could no longer remain a bystander. In the worst-case scenario, a great war involving the Three Worlds would have erupted. That is why the Six Kings could not lay a hand on the Demon King.”
Lilia took over the explanation from Aoi, her tone heavy. That was likely what the Six Kings feared most. If it were only the Human Realm, perhaps the Six Kings could have made a ruthless decision to suppress it by force to protect the Demon Realm.
But if the God Realm moved, it wouldn’t end there. If the legends of the ancient war between the Demon and God realms were true, their power was more or less equal. Conflict between them would have meant certain devastation for the Demon Realm, and the Six Kings wanted to avoid that at all costs.
“A war that would engulf all three worlds. To avoid that, they needed someone… in the Human Realm, the weakest of the three, they needed an existence powerful enough to defeat the Demon King—someone who could carry the hopes of humankind. A hero who could sit at the negotiating table with the Demon Realm…”
“That was… the First Hero…”
“Exactly. There are various theories regarding the summoning of the First Hero. Some say the Creator God, fearing a great war, gave the Summoning Magic Circle to humankind as an oracle. Others say the Six Kings secretly requested cooperation from the God Realm. Some even claim a magic circle of unknown purpose had existed in the Human Realm since ancient times… Because of the chaos of the era, no clear records remain, but the Hero Summoning was eventually performed in the Kingdom of Sinfonia.”
And that was where the First Hero made her entrance. I wondered what kind of person she was. There was no doubt she came from the same world as us, but was she Japanese?
“I have heard that the First Hero’s journey was incredibly grueling. While traveling through a world in total disarray, she saved countless lives, gathered comrades, and eventually defeated the Demon King after a fierce battle.”
It sounded like a classic fantasy story, but the reality must have been brutal. Just like us, she probably struggled just to understand what was happening at first. Back then, there wouldn't have been anyone to explain the differences between this world and Earth as clearly as Lilia was doing for us.
To be sent all alone to a completely unknown place, searching for information through trial and error while challenging a powerful enemy for the sake of total strangers… I knew I could never do something like that.
“…Following the defeat of the Demon King, the Six Kings moved with incredible speed. They immediately explained the situation to the First Hero, and together, they eradicated the remaining Demon King Army remnants in an instant. Thanks to the First Hero’s cooperation, they were able to demonstrate to humankind that they had no intention of continuing the war, preventing a total collapse into conflict.”
“…But that doesn't mean there was no lingering resentment, right?”
“Yes, as Aoi says, what was established between the Human Realm and the Demon Realm at that time was merely a treaty of ceasefire and non-aggression. Even with the Demon King gone, the Human Realm was exhausted and traumatized.”
That made sense. Defeating the villain didn't just fix everything. If anything, humankind’s fear and hatred of demons would have been at an all-time high.
“However, the First Hero did not stop there. After hearing the full story from the Six Kings, she realized that the lack of communication between the Three Worlds was the root cause of the tragedy. She resolved to ensure it would never happen again.”
“……”
“First, she persuaded the Six Kings to provide resources and food to help the exhausted Human Realm. Then, she traveled to the God Realm to negotiate with the Gods. It was not an easy path. She faced friction and prejudice at every turn. Yet, she never gave up. She traveled to every corner of the world, speaking until her throat was raw… She desperately appealed to everyone, saying, ‘Even I, who came from a completely different world, was able to find common ground. I have come to love this world from the bottom of my heart.’”
Just how strong was this person? She must have faced constant rejection at first, yet she never broke. Continuing those negotiations must have been a much harder and steeper path than simply fighting the Demon King.
“…Slowly, the First Hero’s supporters grew. Gates were built between the realms, and opportunities for interaction increased. Her dream of peace eventually became a future that many desired. Finally, after nine years, at the very place where she had defeated the Demon King—the site where her second battle had begun—the kings of the Human Realm, the Six Kings, and the Creator God gathered. Under the witness of the First Hero, the Friendship Treaty of the Three Worlds was signed.”
“…That’s incredible.”
Hina’s whisper mirrored my own thoughts. It sounded like a grand epic. But in this world, it wasn’t fiction; it was history. That was why the First Hero was still a legendary figure today.
“Thus, the First Hero’s battle ended. At the site where the treaty was signed, the Three Worlds cooperated to build a city. Its name is ‘Hikari,’ the city that hosts the main celebrations of the Hero Festival, named after the hero herself.”
Wait… Hikari? If the city was named after her, then the First Hero was—a woman?
“And since then, a festival has been held once every ten years to match the number of years she spent traveling, honoring the great hero. That is the Hero Festival. This has been a long explanation. Do you have any questions?”
“…What happened to her afterward?”
Lilia finished her story with a quiet exhale. After a moment of silence, I tentatively raised my hand.
I understood now why she was so revered. She was the symbol of peace, a true hero who faced impossible odds and never faltered. But what happens to a hero after the battle is won? That was what I wanted to know.
“…The details are unknown. After the Friendship Treaty was signed, the First Hero suddenly vanished from the public eye. Later, on a hill near the site of the treaty, the sword she favored and a stone monument engraved with a Summoning Magic Circle were discovered. On the back of that monument, she had left a message in her own hand.”
Lilia recited the words from memory, her voice soft.
‘My battle as a Hero has ended. I am truly glad I came to this world. There were those who encouraged me. There were people who cheered for me. There was everyone who supported me. Because of them, I was able to keep going. I didn't achieve this because I was called a Hero. It was because every person in this world found the courage to take a step forward that the Three Worlds were able to connect. I am not the only Hero. Everyone living in this world is a great hero—so I know it will be all right from now on. I love this world. I pray that it remains a peaceful world full of smiles forever—Hikari Kujo.’
“…The sword and the monument are protected by incredibly powerful Preservation Magic. They remain today exactly as they were a thousand years ago.”
“…Do you think she went back to her own world?”
“No one knows. Some believe she returned home, while others believe she remained here in secret. However, information discovered in recent years suggests that… the Underworld King may be the only one who knows the truth.”
A hero who accomplished the impossible and then faded away. It really was like a legend. I didn't know much about Preservation Magic, but it sounded like Lilia had more to share.
“About two hundred years ago, a hidden passage was found in a cave the First Hero was known to have visited. Inside were a journal and a letter. The Preservation Magic on these wasn't as strong, and the journal had weathered away into dust, but part of the letter—written in characters from another world—was deciphered by a Hero invited to a previous festival.”
Lilia placed a sheet of paper on the table. It was a copy of the letter. Though some of the text was missing, the parts written in Japanese were clear: words of gratitude and farewell addressed to the Underworld King.
“The Underworld King has refused to discuss her fate, citing a personal promise. However, given that the Underworld King was the first to support her ideas and provided the most assistance during her travels… it is widely believed that the one who cast the Preservation Magic on the monument was the Underworld King.”
“…I see.”
The First Hero’s ultimate fate remained a mystery, but I finally understood why she was so beloved. Compared to the pathetic Demon King, she was a person of incredible character.
Dear Mother, Father—there is still so much I don't know about this world. But I can say one thing for sure: the Hero really was a great hero.