Leaving the Archives, the three reached the "Corridor of Principles" at the outermost edge of Churyo.
As they ventured further, the fog grew denser with every step. Visibility was reduced to no more than an arm’s length; there were moments when even the flagstones beneath their feet seemed to sink into the depths of the mist and vanish.
Asahi led the way, tapping the ground with the tip of his scabbard to feel for the path. The dry clicks of wood on stone became the only thread holding them together.
Bringing up the rear, Kuon clutched the Catalogue to his chest, dimming the blue glow of his prosthetic eye to its lowest setting. In a fog this thick, a strong light would only wash out one's vision, making it impossible to see anything at all.
Koyoi walked on, relying on the sight of Asahi’s back and the steady presence of Kuon behind her. Inside her pouch, the Drop pulsed with a faint, slender rhythm. Something was waiting ahead.
The "Corridor" was a narrow bridge suspended over an abyss. It was just wide enough for three people to walk abreast. Stone railings lined both sides, but beyond them lay a darkness so deep the bottom was invisible.
The stones underfoot were damp. Every time a boot touched the surface, it made the sound of a thin film of water breaking.
Whenever the lanterns on the railings flickered unnaturally, particles of information fell around them like snow. The sound of wind chimes was no song of salvation; it echoed like a thin, high-pitched scream heralding the end of the world.
Koyoi kept moving, constantly measuring the distance of the sounds. A chime that seemed close would suddenly drift away, while a distant one would snap back right beside her ear. The bridge itself was distorting its own depth.
Kuon opened the Catalogue, attempting to pluck the coordinates just as he had at the Well. But the characters refused to surface. The moment they touched the blue light of his eye, they sank back into the grain of the paper.
Even the beams of light refracted mid-air, bending toward impossible directions. This was a place where one could not simply walk straight.
Kuon increased the output of his prosthetic eye. The blue light intensified for a heartbeat, nearly catching the silhouette of something at the end of the passage—but in the next instant, the void swallowed it whole.
Koyoi placed a hand on the railing, trying to peer ahead. The pale blue flames of the lanterns continued in a dotted line, but past a certain point, they simply vanished.
Asahi stopped. He tilted his head back, scenting the air like a hound.
Then, the wind shifted.
It was no longer the damp breeze of before. A horizontal wind, sharp as a blade, lashed against their cheeks.
The flames in the lanterns tilted all at once, and several were blown out. The darkness of the bridge deepened further.
Cold air surged up from below. The abyss was breathing. And along with that breath, something was climbing up from the depths.
Koyoi felt it instinctively. The Drop inside her pouch quickened its pulse rapidly, thrumming a warning.
Asahi spoke in a low voice.
"...The wind is changing. It's the wind that heralds the arrival of the 'Cleaner'—the most cruel facet of the Principles."
His voice held a note of caution, mixed with a faint trace of exhilaration. Inside its scabbard, his sword gave a soft, metallic ring.
Asahi’s posture shifted. From his toes to the crown of his head, it was as if a single steel wire had been threaded through him. It was the "serious" stance Koyoi had seen many times before.
Kuon tucked the Catalogue under his left arm and switched his prosthetic eye to combat-analysis focus. The blue light stretched out into a sharp edge, carving through the gloom.
"It’s coming... It’s right next to us!" Koyoi cried out.
She pulled her pouch close, trying to let the warmth of the Drop circulate through her entire body. The wind whipped her hair into a frenzy, and particles of information stung her skin. It was painful just to keep her eyes open.
Still, Koyoi did not look away. If she closed her eyes, she would lose sight of it. And if she lost sight of it, her very form would be eroded away.
The Drop gave a particularly powerful pulse. Its warmth wrapped around her like a shield, softening the blade-like wind just a little.
With a roar, Asahi kicked off the ground. The sound of his sword leaving the scabbard tore through the dark. A silver arc split the wall of wind in half.
The impact shuddered through the bridge, sending dust geysering up from the joints of the flagstones.
Kuon’s blue light read the opening beyond that gap. Asahi carved the path, Kuon deciphered it, and Koyoi bound them together. Their roles meshed together perfectly, without the need for a single word.
After a brief, violent exchange, the wind weakened slightly.
Asahi regripped his hilt with a palm stained with a trace of blood and smiled.
"...Let's go. I've left the answer on the other side."
Koyoi nodded. Kuon clutched the Catalogue to his chest.
The three began to walk toward the heart of the passage.
Behind them, the lantern flames receded one by one; ahead of them, the endless darkness stretched on. Yet, their pace did not falter.
The sound of the wind chimes faded, replaced by the steady rhythm of their footsteps. Koyoi pressed the pouch against her chest, layering her own heartbeat over the pulse of the Drop.
The warmth spread from her fingertips to the depths of her soul. It wasn't that she wasn't afraid. But even so, they had come this far.
Beyond the point where the countless predecessors sleeping in the Archives could not reach—that was where they were going.
Deep in the darkness, she thought she saw a glimmer of light. It might have been an illusion. It might have been a fragment of the answer.
She didn't know yet. But the three of them did not stop.
In this phase, our survival depended not on raw momentum, but on a deliberate layering of precision. Kuon took the lead by drawing a sharp line between what was certain and the vast, unconfirmed void. Sharing this clarity, Koyoi committed the same truth to her records. Maintaining this unwavering order ensured that the sparks of misunderstanding never caught fire. In the face of crisis, stability is not found by multiplying tasks, but by grounding the very first step in absolute certainty.