The first wave reached them before Rayleigh had even finished giving the order.
More than twenty Enhanced Species poured from the newly opened passages, crowding the narrow spaces between the brood sacs before spreading toward the three major roots.
Some still bore obvious traces of the experiments that had produced them—metal rods along their spines, enlarged absorption mouths, reinforced limbs built around techniques stolen from particular adventurers—while others had been forced out before their bodies were finished.
One dragged an incomplete leg behind it as it ran, another had armor covering only half its chest, and several still had black cords buried in their backs where the central mass had hauled them upright before they were ready.
Individually, many of them were crude.
The network made that far less important.
Pulses raced through the black strands covering the chamber, and the disorganized charge reorganized almost immediately.
Larger monsters pushed to the front while faster ones split toward the flanks.
Absorption types moved into positions where they could intercept released Zanpakutō, and the more specialized creatures headed directly for the adventurers they had been designed to counter.
Rayleigh watched the formation take shape in seconds.
'So this is what happens when the teacher stops holding back.'
Until now, the source had been collecting techniques one monster at a time.
Faced with the threat to its roots, it had finally begun using everything it knew as part of a coordinated whole.
Ais moved beside him as three creatures closed around the signal root.
Gonryōmaru was still released, but the lightning along its blade had been compressed to a thin glow hugging the edge.
She no longer flooded the battlefield with electricity simply because she could; each discharge lasted only as long as the strike that needed it.
One Enhanced Species met her with Raul's copied guard.
Ais cut toward its shoulder, waited for the creature to adjust, then changed direction before the blades touched.
Gonryōmaru flashed once across the black strand on its back and severed the connection before the absorption mouth along its side could turn toward her weapon.
The change was immediate. Its disciplined guard disappeared, and the creature lunged with both claws like an ordinary Dungeon beast.
Ais slipped past it and shattered the magic stone on her next step.
By then Rayleigh had already gained several meters toward the root.
The central mass responded by sending four more creatures into his path.
Benihime met the first weapon in a shower of sparks.
Rather than contest the strike head-on, Rayleigh redirected it, turned past the creature's shoulder, and cut open the controlling strand along its back without slowing down.
He left the disconnected monster behind.
Ais dealt with its core before it could recover.
Neither of them had any reason to kill every creature placed in front of them. The roots were the only targets that mattered.
Across the cavern, Tsubaki reached the energy channel with Asfi close behind.
The enormous root disappeared into several meters of Dungeon wall, where pale new stone had repeatedly grown over the invading tissue only to crack apart again under pressure from within.
Asfi had found the general junction before the horde arrived, but the true point where the parasite entered the Dungeon remained buried beneath layers of fused growth and rock.
Tsubaki planted herself between Asfi and the incoming monsters.
"Find the part I actually need to break. I'll keep them off you long enough to tell me."
Asfi was already pulling three narrow probes and a small vial from her equipment pouch.
"I intend to. Try not to destroy so much of the wall that I can no longer identify what we're looking at."
Tsubaki glanced at the massive root embedded in several meters of stone.
"You're asking that while carrying explosives?"
"Mine are precise."
Tsubaki laughed.
"So are mine."
Then the monsters reached her.
The first had clearly been built with Tobiume in mind.
Three enormous mouths swelled across its torso, while layered plates protected the joints Tsubaki had targeted repeatedly in earlier battles.
It charged with its arms spread wide, almost begging her to send a fireball straight into the center of its body.
Tsubaki stepped forward and smashed sealed Tobiume across its jaw instead.
The impact spun the larger creature halfway around.
Before it could recover, she hooked one foot behind its ankle and drove her shoulder into the reinforced torso, sending it crashing onto its back.
"You spent all this time preparing for Little Ume and somehow forgot I'm a Level Five with a sword."
The creature tried to rise. Tsubaki stamped on one wrist and drove Tobiume through the gap beneath its chin.
The magic stone broke.
Another monster immediately took its place, this one carrying a broad sword and settling into a compact stance copied from Ais.
Tsubaki raised Tobiume as though she intended to meet the guard properly, then kicked a loose slab of Dungeon stone straight into the creature's knee.
Its stance collapsed.
Tobiume followed.
The sword broke first and the shoulder behind it broke a moment later.
Tsubaki continued fighting without releasing Shikai, deliberately giving the source as little additional information as possible while Asfi worked behind her.
One probe disappeared into a crack beside the energy root.
Asfi pressed two fingers against the exposed end, felt the vibration travelling through the metal, then withdrew it and tested a second point farther down.
The new probe shook much harder.
Her eyes narrowed.
She poured several drops of clear liquid onto the pale stone around the section.
The Dungeon material hissed on contact but the black growth underneath did not.
"Tsubaki. Three meters above the floor, just left of the largest split. The visible root is wrapped around a narrower section that actually enters the wall. I need the outer growth removed without damaging the inner junction."
Tsubaki glanced back once.
"Got it."
She released Tobiume.
"Snap, Tobiume!"
The blade changed into its modified flame-shaped form, crimson liquid flowing through the groove along its center.
Two absorption monsters immediately changed direction toward her.
Tsubaki ignored them.
She aimed at the Dungeon wall above the root instead of the black tissue itself.
The first fireball exploded against the stone and tore away a broad layer of pale rock without feeding spiritual pressure directly into the parasite.
She adjusted the angle and fired again, breaking apart another section.
Asfi raised one hand.
"Enough!"
Tsubaki stopped at once.
A narrower black column had been exposed inside the larger root.
Its pulse was different from the tissue surrounding it, and faint energy could be seen moving through it from deep within the Dungeon toward the central mass.
Asfi smiled faintly.
"There you are."
She began placing charges.
...
The material root posed a different problem entirely.
Ardi and Lyra had reached the junction, but nearly half a dozen brood sacs had been clustered around it.
Several had already ruptured, and the creatures emerging from them were still being fed through smaller channels packed with glowing magic-stone fragments.
One of the defenders had clearly been built around Nejibana. Its broad body contained multiple channels full of dark fluid, and wide mouths opened along both arms whenever Ardi moved the trident.
The central mass had learned that absorption worked best with sustained contact, so this creature had been designed to expose as much consuming surface as possible whenever water approached.
Ardi looked past it toward the fragments streaming through the black channels.
"I don't need to hit you with water."
Lyra heard her and grinned.
"Good. I was hoping you'd noticed."
The creature charged.
Ardi met it with Nejibana's shaft rather than its blades, rotating the trident across her body and striking the monster hard across the neck.
There was nothing for the absorption mouths to consume.
Lyra moved with her.
Arachne's silk anchored to the broken brood sacs on either side of the corridor instead of wrapping directly around the monster.
As soon as it stepped between them, she crossed her hands and pulled.
The threads tightened into an invisible barrier.
The monster recognized the trap and swept both arms outward. Blade-like edges along its wrists cut through Arachne's silk.
Lyra had expected that.
The severed threads brushed across its forearms as they snapped, carrying Arachne's toxin into the shallow wounds Ardi's trident had already opened.
The monster's next step came just slightly late.
Ardi needed nothing more.
Nejibana drove between its ribs and shattered the magic stone before the absorption mouths could close around the weapon.
The body dissolved.
The black cord attached to its back tried to recoil into the material root.
Lyra caught it first.
Arachne's silk wrapped around the strand, and she allowed the contact to remain for less than a second.
Spiritual pressure immediately began draining out through the threads, but Arachne's toxin travelled in the opposite direction.
The black cord spasmed. Its pulse became uneven, and several nearby brood sacs twitched out of sequence.
Lyra cut the connection before the drain reached her gauntlets.
"There. It still hates the poison."
Ardi looked at the thick material channel.
"Could you poison the whole root?"
"Maybe, if I wanted Arachne sucked dry and my brain dragged out through my fingertips. I'd rather not test it."
Ardi nodded.
"Then we only need to confuse it for a moment."
"Much better plan."
They advanced.
Two more Enhanced Species emerged from the surrounding sacs.
Lyra used the environment to make the passage unreadable, weaving threads between broken pillars, discarded shell fragments, and cracked stone until the monsters had to choose between slowing down to search for silk or charging blindly through spaces they could no longer trust.
Whenever one committed, Nejibana's reach punished it.
Ardi had spent years learning how to fight with a trident, not merely relying on the power released by one.
Her hands slid along the shaft as the distance changed, constantly adjusting leverage while the three blades controlled far more space than an ordinary sword.
The source had studied Nejibana's water.
It had paid considerably less attention to Ardi herself.
The final defender tried to catch the trident between two absorption mouths.
Ardi shortened her grip instead and drove the butt of Nejibana beneath its jaw.
The creature's head snapped upward.
Arachne's silk looped around its exposed ankle, and a single pull destroyed its balance. Ardi brought the trident down through the magic stone.
With the immediate defenders gone, they finally reached the material root.
The channel was almost transparent at the junction.
Hundreds of broken magic-stone fragments travelled through black fluid inside it, moving toward the central body and the remaining brood sacs.
Ardi adjusted her grip on Nejibana.
"I can force them back."
Lyra studied the thick tissue.
"And what happens when it starts drinking your water?"
"I won't leave it there long enough."
Ardi turned the trident, gathering a narrow stream around the center blade.
Rather than attacking the outer surface, she thrust into a crack that the Dungeon's repeated attempts at sealing had already opened.
Nejibana pierced the channel.
"Now."
The water entered from within.
The reaction was violent.
Absorption mouths began forming along the root's surface, but none could reach the stream because Ardi was forcing it through the internal channel itself.
The current struck the incoming flow of magic-stone fragments head-on and drove them backward.
For several seconds, the two flows fought inside the root.
Then a glowing shard shot out through the rupture beside Nejibana.
Ten more followed.
Then dozens.
The entire flow reversed, spraying magic-stone fragments across the cavern floor.
Ardi tightened both hands on the trident and increased the pressure just long enough to widen the internal tear.
"Lyra!"
Arachne's silk entered from both sides.
Lyra did not try to bind the entire root.
She anchored separate strands to the torn edges and pulled outward while the water pressure was already forcing the tissue apart.
The material channel split lengthwise.
Dark fluid poured across the floor, and the brood sacs connected to it immediately began to shrink.
They were almost through.
Lyra looked across the cavern toward Rayleigh.
"Hold it there. We cut when they do."
Ardi nodded and reduced Nejibana's water before the root could establish a sustained drain.
The damaged channel continued pulsing weakly around the trident.
They were ready.