### Side Story: [
In a certain building, one particular room.
Everything in the office was unified in black—from the walls and floor to the furniture. A stark, oppressive space.
Two men faced each other there.
One was a young man who appeared to be in his mid-twenties, seated in the room's main chair. His left arm was missing, and an eyepatch covered his right eye.
The other was a man in his late forties, his original black hair now streaked with white. The usual mild-mannered demeanor he showed the world had vanished; what remained was his true atmosphere—cold, commanding, and heavy.
Judging purely by appearance, the older man seemed to hold the higher position. But in reality, it was the younger one who stood above.
"I apologize for visiting without an appointment, Grandmaster."
"You wouldn't come without reason. This must be something serious."
"Yes. Given the nature of the matter, it will likely reach your ears soon anyway—probably with embellishments and exaggerations attached. That's why I came directly to report it myself."
"Hm. Go on, then. What happened?"
"Three days ago, an irregularity occurred in the Southern Great Labyrinth under my jurisdiction. An explorer witnessed the floor boss of the 92nd floor—the one commonly called the black dragon—operating outside its designated boss area."
"...I see. A glitch caused by the Western one disappearing? Or was it intentional? We won't know until we keep analyzing."
"With all due respect, I believe it's the former."
"Oh? And why is that?"
"The floor boss is supposed to be a powerful defensive mechanism. We allocate tremendous resources to bind such a formidable beast in place. If floor bosses could roam freely within their layer—especially in the vast deep floors—there would be a real chance of bypassing them entirely and advancing to the next level without ever encountering them. Would we deliberately introduce such a risk?"
"That does make sense. For now, we'll treat this as a temporary malfunction triggered by the Western Labyrinth's disappearance. It's probably already been corrected. Next likely candidate is the Eastern one?"
"That would be my guess as well. Neither the West nor the East has deep floors. The North is unclear, but the South won't see further progress for quite some time."
"Make sure I'm contacted the instant the Eastern one vanishes. And if any similar irregularity occurs again, report to me immediately."
"Understood."
"Is that all? It's certainly information I'd prefer to know early, but it doesn't seem urgent enough for you to rush here personally."
"There is one more report. In fact, I believe this one will be far more beneficial to you, Grandmaster. As you said, the irregularity itself has likely already been resolved."
"Beneficial, you say. What is it?"
"Related to the earlier irregularity—a certain explorer has single-handedly defeated that black dragon."
"That's impressive. It was Oliver Cardiff, right? So he finally blossomed."
"No, sir. It was not him."
"...What? There shouldn't be anyone else capable of soloing a deep-floor boss— Wait… Don't tell me… His name isn't Orun Dura, is it?"
"You already knew of him? He was with the Hero Party but remained completely unknown until now. As expected of you."
"No way… It can't be… Impossible… If he truly had the power to solo a deep-floor boss, he never would have chosen to be defeated— Wait, no…"
"…Is something the matter?"
"Has there been any unusual change in him recently?"
"No. Nothing of the sort has been reported by those in charge of monitoring him."
"Then how has his attitude toward the Guild been?"
"Perfectly normal, from what I hear. When he reported on the black dragon the other day, he was the same as always."
"So that means… he somehow acquired the strength to defeat a deep-floor boss on his own, all while staying exactly the same on the surface? Kukuku… Ahahahahaha! How far gone is this guy?! What a masterpiece! In that case—keep dancing for me, just like this! Become my savior, Orun Dura! If you do, I'll wipe the slate clean on everything you did to me! Ahahahahaha!"
"Um… Grandmaster…?"
"Ah, sorry. Got a little carried away. I'm fine now. You're right—news of someone soloing a deep-floor boss could easily get exaggerated with embellishments. And heh heh… this is definitely beneficial information for me. Thank you."
"You are too kind."
"Is there anything else? If not, you're dismissed."
"Yes. Then, if you'll excuse me."
The white-streaked man gave a respectful bow and left the room.
Now alone, the young man addressed as Grandmaster murmured to himself.
"Never wake from the dream. Just keep dancing like this—for the sake of my ambitions! Ahahahahaha!"