At Infernal Corridor Academy, inside a massive classroom shaped like an arena, dazzling spotlights illuminated the towering walls on all sides.
This was no ordinary classroom. Instead of a simple square layout, it had been built like an indoor coliseum: oval-shaped, with tiered rows of seats encircling the central arena. The seats rose higher and higher, until the last row nearly brushed the ceiling.
Now, halfway into the fourth class of the day—
At the center of the arena, demons were locked in a fierce battle.
In the farthest row sat a brother and sister, waiting silently.
【Time Remaining: 3 hours 30 minutes】
【Mission Objective 1: Academy exploration rate must exceed 60%. Current progress: 748%】
【……】
They were silver-ranked challengers from the Kingdom of Yaloran.
There had already been suspicion that a demon had infiltrated among the challengers, and the siblings now kept their eyes fixed on the Shadow World’s mission indicators.But these numbers… looked broken.
At the start of the fourth class, exploration progress had been only 40%. Then, suddenly, it began climbing at an outrageous speed, shooting upward without pause.
From their own exploration earlier, they had roughly determined that given the academy’s size, fully exploring the teaching zones should indeed yield a progress value far beyond 100%.
However, by the Shadow World’s mechanics, 100% was calculated to represent the absolute maximum exploration possible within twelve hours by all challengers combined.
And yet—
The current figure had already surpassed reason itself, continuing to climb, ticking upward every few moments without stopping!
The siblings simply couldn’t comprehend what was happening.
By the end of the third class, everything had still been normal. Based on the progress changes, it was clear all three teams had cleared level-3 classrooms, contributing a combined 18% increase.
From their investigations across earlier classes, the siblings had also learned some intelligence:
Tonight, an uninvited inspector would arrive at the academy—someone capable of striking fear even into senior professors.
【Mission Objective 2: The Source of Danger Tonight】—without a doubt, referred to this “inspector.”
His identity, his purpose, and his connection to the human challengers hiding within the academy… these were mysteries that required all three groups to meet and share information before the puzzle could be solved.
That was how the Shadow World was meant to be played.
And yet—
No matter how many signals or coded marks the siblings left during class breaks, the other four challengers showed not the slightest intention of meeting with them!
In the Shadow World, where challengers scattered at the start and identities were hidden, one could not know another’s identity without deliberate contact.
Under these conditions, the correct strategy was obvious: skip the fourth class, and devote every effort to locating and joining the others.
But then—
The academy abruptly issued an emergency regulation:
【All students must return from the functional areas to the teaching zone. During the fourth class, attendance is mandatory. No one may leave. A large number of teachers will patrol the hallways; any student found wandering will first be driven back into class, and if they resist, executed on sight. Furthermore, all level-3 classrooms will close during the fourth class.】
It was as if the Shadow World had suddenly shifted gears into runaway mode!
With no choice, the siblings had entered a level-2 classroom, just to survive another period.
“…Brother, could it be someone triggered the wrong mechanism… and brought the danger ahead of schedule?”
The girl’s voice trembled. Her hollow gaze sought a shred of hope to cling to—but found none.
“…”
The young man bit his lip, unable to answer.
Fear and anxiety churned inside him, nearly overwhelming him. But as her older brother, he could not let his sister’s terror deepen.
“…Don’t be afraid.”
He murmured softly, trying to soothe her.
From the first class onward, he had been monitoring the exploration rate, using the shifts to infer what difficulty levels other groups were challenging at different times.
Two challengers had remained in the teaching area, clearing classrooms step by step, at a pace similar to theirs. Yet, oddly, they showed no interest in linking up—acting as though they didn’t care whether the Shadow World could be cleared at all.
And two others, despite having the strength for level-3 classrooms, had practically vanished. From the second to the fourth class, they had skipped two entire periods—apparently wandering aimlessly in the functional areas!
“…O Goddess… we’ve done nothing wrong. Why must we be thrown into this demon academy? If you still watch over us, please—send someone to save us…”
The girl bowed her head, hands trembling in desperate prayer.
When one’s only recourse was to pray to the gods—despair was already near complete.
At that moment, the classroom doors swung open.
The metallic clatter of the lock echoed sharply across the room.
Then—a large group of demon teachers strode inside. Their steps were steady, purposeful, as if clearing the way for someone waiting outside.
The sudden intrusion froze every demon student in place, like time itself had stopped.
And then—from beyond the door—
A black-haired, green-eyed Radiant Demon stepped inside, with the bearing of a leader.
He halted for a moment, scanning the room.
“Take every student here to the Principal’s Office.”
With that, he ordered the class suspended, and all students escorted away.
It was like watching captives being marched off to a concentration camp.
In the back row, the siblings felt their last hopes shatter.
The moment they had dreaded… had finally come.
But what twisted kind of Shadow World mechanism was this, that the principal himself had to come and erase them?!
The Radiant Demon seemed to sense the unease spreading through the class. His brow creased slightly.
“Students, do not be afraid. The Principal’s Office is safe, and very spacious. The academy is undergoing a sudden inspection, and this classroom’s course risks being flagged as noncompliant. I must have you avoid it temporarily. Once the fourth class is over, you will return to campus as usual—and each of you will receive three credit coins as compensation. I, the principal, give you my word.”
Raising his hand, he gestured for calm, his voice reassuring.
At once, the demon students quieted. Their faces even lit with surprise at the unexpected boon.
None of them doubted his words.
For a principal who commanded such respect from senior professors, there was no need to resort to convoluted tricks if he wished them harm.
In the back row, the siblings exchanged a tense glance.
Their unease remained, but now mingled with confusion.
Was it possible… this principal was helping them?
Even protecting them?
Yet no matter how they thought about it—
The principal of a demon academy… this Radiant Demon could never be on a challenger’s side!
His profound, commanding presence, before which even the mightiest professors bowed in reverence—he was without doubt the most evil, most terrifying leader of demons in this Shadow World!
Surely, the academy itself must have encountered some problem. Perhaps the Shadow World’s mechanisms had glitched at just the right moment, giving them this sliver of reprieve.
The more they tried to decipher the Shadow World, the more baffling it became.
And yet—
For the siblings, for the first time in hours, it seemed a faint path of survival had opened before them.