The Second Letter: The Faceless Knight
With the mystery of the first letter resolved, the club members gathered around me once more, and I picked up the second of the four letters. As all eyes focused on it, I began reading the next request aloud, slowly.
To the members of the Paranormal Investigation Club.
I have a mystery from Everlight Academy that I wish you would investigate. Recently, I heard a bizarre ghost story from a friend's hometown. It was so strange and incomprehensible that ever since hearing it, I haven't been able to sleep well, tormented day after day. The name of that ghost story is the Faceless Knight.
The tale begins in my friend's hometown, a slum that turns especially cold and desolate in winter. According to the handed-down stories, there once lived a knight of exceedingly cruel disposition. He valued human lives like insects, but his swordsmanship was unparalleled, and during a war with the neighboring territory, knights were precious, so no one could restrain him. Every time he bought a new sword, he would test its blade by mercilessly slashing the impoverished. But even the greatest skill has its limits when it comes to turning a blind eye. After the war ended, he was executed for slaughtering too many of the common folk. It was a bitterly cold winter with fierce winds.
Yet even in death, that cruel knight's soul could not find rest and still wanders the slums. He appears only in winter, the season of his death, slashing the poor and destitute with an invisible blade, just as he did in life. The knight himself is invisible and intangible, and those cut by his sword suffer wounds torn like paper cuts, without a drop of blood. This phenomenon occurs every winter on days when the wind blows strong. Because it resembles an unseen knight swinging his blade, it's called the Faceless Knight's Sword Marks.
Please, Paranormal Investigation Club, uncover the secret of the Faceless Knight.
Judging by the handwriting and phrasing, the writer of this second letter seems to be the same person who sent the first one. What on earth is this student's motive for sending these ghost stories?
At that moment, the other students, their faces much brighter, let out sighs of relief.
"The ghost story isn't set at Everlight Academy!"
"So this one probably isn't a real ghost story either! Ghost stories outside the academy can't manifest, right?"
Rozalia and Rone, having heard the letter's contents, laughed and breathed easy.
"Exactly. Manifestations only happen at Everlight Academy and on this island."
"Once the Outer God revives, the whole world will be engulfed in ghost stories, but that's only after the revival. In other words, until then, the world outside the academy is perfectly safe."
As Elaine and Aurora explained, the reason was simple: the ghost story in this letter wasn't real. That meant no need to risk our lives to resolve it. But relaxing too much wasn't wise. Even if we could let our guard down for now, I'd prefer we do so only after clearing all four letters. We got lucky that the first two weren't Everlight Academy ghost stories, but the third and fourth might not be so kind.
Seeing the club's relieved expressions, I shook my head and countered.
"That's true, but if this ghost story starts circulating within the academy, things change. Right now, it's just one student's local legend, but if it spreads by word of mouth among the students, it could be reclassified as an Everlight Academy ghost story."
My words turned the students' faces serious. The relief from moments ago had vanished.
"Then we need to resolve this one quickly."
"Yeah, it looks like it could be incredibly dangerous if it manifests."
With that, the students shifted to earnest discussion of the letter's contents.
From afar, a female student watched the Paranormal Investigation Club members puzzle over the letter. She was the requester who had sent it. A leisurely smile spread across her face.
"Heh. This one won't be easy to solve. Even I agonized over it day and night before barely figuring it out. And unlike Lighthouse Hill, where you can scout the site yourself, investigating the Faceless Knight firsthand is impossible..."
With a wicked grin, she imagined cornering Allen Jest this time, picturing his downfall—until a loud voice from inside the club announced a breakthrough. The words that reached her ears froze her sly smile in disbelief.
"I got it!"
Elaine shouted as if struck by sudden insight, her eyes brimming with conviction.
"It's vacuum!"
"Vacuum?"
Rone and Rozalia voiced their confusion in unison at Elaine's declaration. Aurora furrowed her brow slightly, watching her intently.
Elaine, brimming with confidence, began explaining her reasoning.
"The hints are 'winter' and 'days with strong winds' in the letter. On cold days with high winds, vacuums form naturally more easily!"
"...What's a vacuum state?"
Rozalia raised her hand to ask, and Aurora answered.
"A vacuum state is when the pressure in a specific space is extremely low because almost no matter, including air, exists there. Simply put, think of it as an empty void with nothing in it."
"...Isn't most space already empty?"
"...Are you serious?"
"N-No, I'm kidding! I totally get it!"
Rozalia nodded with an expression that clearly showed she didn't understand at all. But we were mature enough not to press her on it and just let it slide.
Ignoring Rozalia's reaction, Elaine pressed on.
"Exactly—that naturally occurring vacuum in the air sharpens like a blade of wind and slices the skin!"
"Wow! Amazing, Elaine!"
Rone clasped her hands in admiration. Aurora bit her lower lip as she listened, her eyes flickering with awe at Elaine's lead—and a hint of humiliation.
"To think such a theory existed...!"
Convinced by the others' reactions, Elaine puffed out her chest and turned to me.
"Well? What do you think? How many points for this answer?"
From afar, the female student stared at the Paranormal Investigation Club in stunned horror, her eyes shaking like a ship in a storm. To think they'd reached the theory she'd barely grasped after sleepless nights so quickly.
"Th-Those nights I stayed up agonizing were... what, exactly...?"
She belatedly recalled that Elaine was the class topper. She'd expected intelligence from the valedictorian, but not this level of wisdom. So distant, so lofty.
As she teetered on despair, Allen Jest's voice carried to her on the island's salty breeze.
"Hmm. Unfortunately, 70 points? No, considering this world's science is generations behind my previous life, 80 points for coming up with that."
Elaine bristled at my score.
"Wh-What's wrong with my theory?"
Her voice dripped with wounded pride.
In truth, this "Faceless Knight" ghost story—like Lighthouse Hill—was one that existed in my past life too. Its name was Kamaitachi. A yokai from Japanese legend, a weasel demon that rides whirlwinds to slash people, leaving cuts like blade wounds but no blood. It matched the Faceless Knight perfectly.
And Elaine's answer—"naturally occurring vacuums sharpening into wind blades to cut skin"—was a popular hypothesis from the late 19th century explaining Kamaitachi phenomena. Honestly, for Hipnia's current scientific level, instantly recalling a late-1800s theory proved how brilliant Elaine was.
But even so, limited by this era's knowledge, her theory had flaws.
"First off, a vacuum means atmospheric pressure at zero. Normal pressure is 1 atm, so a mere 1 atm difference can't tear human skin."
Elaine looked flustered, as if she hadn't anticipated that.
"Uh, no way..."
Then, curiosity piqued, she asked,
"So what's the real secret of the Faceless Knight? You called my answer an 80-pointer, so you must know it, Teacher."
I smiled at her question.
"An answer? What I know is just a more recent hypothesis, really..."
With that, I shared the latest hypothesis on the "Faceless Knight"—the Kamaitachi ghost story—from my knowledge.