The answering impacts came from the lower passage hard enough to send a faint vibration through the barricade.
Every Zanpakutō in the chamber reacted before the last impact had fully faded.
Gonryōmaru crackled at Ais's side as heat spread through Tobiume's scabbard.
Arachne trembled sharply against Lyra's hip, while Ardi tightened her grip on Nejibana as the familiar pull on their spiritual pressure suddenly intensified.
Rayleigh felt all five of his own swords respond at once. Whatever had been summoned was approaching fast.
Finn heard it as well.
His eyes flicked toward the lower passage, but only for a moment before he turned back to the rescue force.
"Continue the evacuation. Gareth, take the first group immediately. Riveria, stay with the rear until every stretcher reaches the upper junction. Nobody stops because of whatever is coming from below."
Loki Familia moved without hesitation.
Gareth took the lead as the first wounded adventurers were lifted onto stretchers, while Riveria fell in at the rear of the column and prepared her Magic in case anything attacked during the retreat.
Raul remained beside Anakitty just long enough to make sure she had been placed with the injured. Lulune and Welf were already being carried out with them.
Finn waited until the last stretcher had passed before turning to Rayleigh.
"You still intend to continue with six people?"
Rayleigh glanced at Ais, Tsubaki, Asfi, Ardi, and Lyra.
"Yes. We've fought enough of these things now to know what feeds them and what doesn't. Bringing more people down only gives whatever's below more techniques to study."
Finn's thumb twitched.
He clearly hated the idea of sending Ais toward an enemy he could not properly assess, but Rayleigh could see him arriving at the same conclusion.
"Then I'll escort the evacuation as far as the junction and mark the route. If you have to withdraw, that's where we'll regroup."
Ais looked at him.
"I'll come back."
Finn held her gaze for a moment, then nodded.
"See that you do."
Another impact came from below, close enough this time for everyone in the chamber to feel it through their boots.
Finn left with the rear of the evacuation group, leaving Rayleigh's team behind.
Tsubaki drew Tobiume and rolled one shoulder.
"Well, whatever they've been growing down there apparently got tired of waiting for us."
Asfi was already filling the empty spaces on her belt with fresh items from the expedition's remaining supplies.
"Considering what happened to the last creature that climbed up here, perhaps it should have remained patient."
Lyra drew Arachne.
"I'm beginning to appreciate your approach to monsters. Considerably less philosophical discussion, considerably more explosives."
Asfi gave her a brief look.
"The explosives work."
Lyra had no argument for that.
Then something entered the passage.
Ais heard it before anyone else.
"Fast."
Rayleigh had barely processed the warning when blue-white light erupted from the darkness and lightning tore across the chamber.
Ais was already moving.
She drew Gonryōmaru as she stepped into the attack, angling the flat of the blade toward the incoming current.
Lightning struck steel and split around her, blasting into the barricades on either side rather than continuing up the route toward the retreating rescue force.
The impact forced Ais back several steps, and her eyes narrowed immediately.
That lightning had carried spiritual pressure, and worse, it was spiritual pressure she recognized.
A creature emerged from the passage.
It was smaller than the giant they had killed in the training chamber, only a little taller than a large human, but there was nothing human about its proportions.
Grey-black plates covered a narrow frame built for speed rather than durability, while six thin metal growths jutted backward from its spine like crooked lightning rods.
It carried a stolen sword in one hand. The weapon itself was ordinary.
The way it held the weapon was not.
Ais went still as she saw the creature lean its weight forward, blade lowered slightly and feet positioned for an explosive first step.
She knew that stance, and Rayleigh recognized it as well.
It resembled the way Ais herself had fought years ago, when most battles began with the same straightforward idea: reach the monster before it could react and cut it down before anything else mattered.
Lightning crawled over the Enhanced Species' sword.
Ais's expression hardened.
"It copied me."
Rayleigh studied the metal spines along its back.
"Only parts of you. That's why you can beat it."
The creature attacked, shattering the floor beneath its first step, and Ais met it halfway.
Their blades collided, and electricity immediately surged through the point of contact.
Ais broke away before the current could properly enter Gonryōmaru, but the Enhanced Species pursued with a thrust that mirrored the angle she had used against the first absorber monster on the thirty-seventh floor.
She slipped outside the attack.
The creature changed direction at once, cutting back toward her neck with timing far better than anything the earlier specimens had shown.
Ais ducked beneath the blade and drove her shoulder into its chest. The impact staggered it just enough for Gonryōmaru to follow, the point slipping beneath one of its ribs.
A mouth opened along the creature's side.
Ais felt the pull immediately and tore Gonryōmaru free before it could drain anything beyond the spiritual pressure already coating the weapon.
The wound began to close as the monster retreated, and neither of them rushed to begin the next exchange.
Tsubaki watched from several meters away, Tobiume still unreleased in her hand.
"That one's definitely better."
Asfi had already come to the same conclusion.
"It also came prepared specifically for Ais. Look at the growths along its spine."
The metal rods were beginning to glow, lightning passing between them before disappearing beneath the creature's armor.
Rayleigh understood.
"The smaller monsters carried what they learned from Gonryōmaru downward. This one was built around it."
Ais heard him without taking her eyes off the creature. Her grip on Gonryōmaru remained steady as the Enhanced Species raised its sword again.
Rayleigh stepped back instead of joining her.
"Ais."
She glanced toward him.
"You take this one."
Tsubaki looked over, but Rayleigh continued before anyone could mistake the decision for recklessness.
"It knows more about your fighting style than anything else we've encountered. If the rest of us join in, we'll give it five more problems to learn from. You're already the one most likely to recognize what it expects you to do."
Ais turned her attention back to the Enhanced Species.
The lightning crawling across its stolen sword looked like Gonryōmaru's power, but that was all it was—an imitation.
"I'll do it."
Rayleigh nodded.
The others spread out through the chamber rather than joining the duel.
Ardi and Lyra covered the side passages in case more Enhanced Species appeared, while Tsubaki positioned herself where she could intercept anything that tried to reach the evacuation route.
Asfi remained near Rayleigh, studying the creature with the same concentration she usually reserved for an unfamiliar Magic Item.
Ais stepped forward.
"Pierce them, Gonryōmaru!"
Lightning coiled around the slender blade, and every mouth across the Enhanced Species' torso opened in response.
Ais thrust, sending a narrow bolt across the chamber.
The creature raised its stolen sword and deliberately took the attack.
Three of the metal rods along its spine lit one after another before the lightning vanished into its body.
Its chest began to glow. A moment later, it swung its sword and sent the stolen lightning straight back at her.
Ais called on Tempest, wind surging around her as she accelerated sideways.
The returning bolt ripped into the stone where she had been standing, but the Enhanced Species was already pursuing her.
Asfi's gaze sharpened.
"It can't absorb and discharge at the same time."
Rayleigh looked at her, and she pointed toward the creature's torso.
"Watch the stones beneath its ribs. When it absorbed Gonryōmaru's attack, three clusters lit in sequence before the electricity reached the rods on its back. While it was releasing the stored attack, every mouth closed."
So there was a storage process involved.
The creature had learned how to take in Gonryōmaru's power, but the energy still needed somewhere to go before it could be used again.
Ais heard Asfi's explanation without turning.
When the monster attacked again, she gave it no lightning to absorb.
Tempest carried her around its thrust as Gonryōmaru opened a shallow cut across its upper arm.
Before the mouth along its side could turn toward the blade, Ais had already moved, leaving another cut behind its knee and a third beneath the shoulder.
The Enhanced Species tried to follow her with the footwork it had copied, only to make its own problem worse.
The Ais it had studied during the earlier fights had been changing constantly, and the Ais standing in front of it had already changed again.
It lunged according to the movement it expected after her next sidestep.
Ais stopped halfway through the motion.
The sword passed in front of her, and she stepped behind its arm before slamming Gonryōmaru's guard into the base of one of the metal spines.
The rod bent beneath the impact, sending an involuntary discharge of lightning through the creature's back.
Ais saw the reaction, and Gonryōmaru seemed to recognize it as well, a faint vibration passing through the hilt.
'There.'
The Enhanced Species twisted around violently, but Ais used Tempest to slip beyond its reach.
The damaged rod continued to spark behind it.
Asfi adjusted her glasses.
"Those rods aren't merely weapons. They're part of the storage system. Damaging one is interfering with the discharge."
A faint smile touched Rayleigh's face.
"Then it copied lightning badly enough to give itself an exposed handle."
Apparently the Enhanced Species reached the same conclusion. It reached behind itself with its free hand and tore the damaged rod out.
Black blood poured from the wound as the remaining five shifted beneath its flesh, redistributing the stored current between them.
Ais watched the adjustment without moving.
'Good. That was what she wanted.'
The creature charged again with its stolen sword held low, and this time Ais met it directly.
Their blades collided several times in rapid succession, but she refused to give the creature a consistent rhythm.
Tempest accelerated one step and vanished from the next, while Gonryōmaru shifted constantly between thrusts, cuts, strikes with the hilt, and attacks deliberately abandoned halfway through, forcing the Enhanced Species to react before she had committed to anything.
Its copied technique was excellent whenever it knew what came next. Ais made sure it never did.
During one bind, the monster released another burst of stolen lightning, and Ais felt the current enter Gonryōmaru.
Her first instinct was to break contact.
She stopped herself.
The electricity crawling across her blade had never belonged to the creature. It had taken that power from Gonryōmaru.
Ais looked at the current and then at the Zanpakutō humming quietly in her hand.
For years, she had treated Gonryōmaru's lightning as a weapon the blade produced for her, something to direct at whatever stood in her way.
The creature had learned to see it in exactly the same manner: absorb it, store it, then release it again.
That was why the imitation seemed so convincing. The Enhanced Species understood lightning as ammunition.
Gonryōmaru understood electricity itself.
Ais tightened her grip as the stolen current reached the guard. Rather than pulling away, she pushed her spiritual pressure into the blade.
The lightning changed direction.
The Enhanced Species jerked, the mouth along its body opening wider as it tried to force the discharge into her.
Ais held her ground, Tempest curling around her boots to keep her stable while Gonryōmaru took control of the electricity passing through the two connected swords.
The creature's lightning flickered and began to bend back toward it.
For the first time since the duel began, the Enhanced Species hesitated.
Ais's eyes sharpened.
"You took it from Gonryōmaru."
The current crawled backward along the stolen sword.
The creature tried to break contact, but Ais followed it.
"So give it back."
Gonryōmaru answered.
Lightning surged into the monster's arm, and the Enhanced Species convulsed as the electricity it had tried to discharge was driven backward through its own storage system.
Two clusters beneath its ribs lit at the same time, while uncontrolled arcs snapped from the metal spines along its back into the ceiling.
The creature tore its sword away and retreated.
Ais let it.
She had already learned what she needed, and Rayleigh had understood it too.
'She isn't overpowering the absorption.'
Ais had stopped treating the fight as a contest over who could produce more lightning.
The creature could consume spiritual pressure, but that did not give it control over the electricity already inside its body.
Gonryōmaru could control that electricity directly.
The Enhanced Species screamed as all five remaining spinal rods flared.
Abandoning any attempt at control, it flooded its entire body with lightning and released the charge in every direction at once.