Calculations Per Second: 872
"How are skeletons born?"
The professor in charge of magical biology closed the book spread open on his lectern. Every student in the room turned their attention forward.
"Ordinarily, they form when a climber dies inside the Tower and their soul becomes trapped in their remains. Being killed by a monster, exposed to a curse, or left for long periods in a place thick with necrotic mana — those are the most common causes."
The professor tapped the blackboard lightly with his pointer. A diagram of a human skeleton was drawn there.
"But even if the soul remains in the body, it does not fully retain the personality it had in life. Memories fracture. Reason is lost. All that remains afterward is hatred directed at the living."
Put another way, every skeleton had once been a climber ascending the Tower.
A warrior who had held a sword and protected their comrades. A mage who had spent decades researching magic. When they died and became imprisoned in their own remains, they became undead that could still use fragments of the skills they had learned in life.
"Next, let us examine the higher ranks."
New writing appeared on the blackboard.
Skeleton Warrior
Berserker
Knight
Warlord
Skeleton Mage
Wizard
Lich
Elder Lich
Mana Lord
"Skeleton Warriors and Mages are commonly found even on the lower floors. But from the Lich upward, the story changes entirely."
The professor drew a line beneath the word Lich.
"Specimens of Lich rank and above can speak human language. They are beings that either restored their shattered souls, or devised a method of retaining their reason even after death."
Someone raised a hand.
"From which floor do they appear?"
"Mostly after the three hundredth."
Low murmurs of awe rippled through the lecture hall.
"Many cases involve climbers who had reached at least the three hundredth floor in life before turning into Liches. They retain their knowledge and experience of magic, so if you ever encounter one, exercise extreme caution."
The professor looked around at the students and smiled.
"With futures as bright as yours, you may well face one yourselves someday."
Iris looked down at the words written in her book.
Lich.
A high-ranking undead that retained both intellect and magic even after death.
If she kept climbing the Tower, it was an opponent she would eventually have to face.
From that day on, Iris imagined battles against a Lich over and over again.
She fought dozens of times inside her head, so that no matter what situation arose, she would never panic.
As the top student of the magic academy, she could win.
That was what Iris believed back then.
And now.
Not even close to the three hundredth floor — a mere thirtieth.
In a place she had never once anticipated, a Lich stood before her eyes.
"A Lich?"
Leon still wore the face of someone who had not grasped the situation.
But Iris knew.
The regenerative power that had restored a shattered skull in an instant. The dense necrotic mana pouring from its entire body. Every feature matched exactly what she had learned at the magic academy.
She needed to run. Somehow contact the instructor and hide quietly until a rescue team arrived.
Her head understood that much. And yet Iris did not retreat.
She was the top student of the magic academy. She had repeated countless image-training sessions, and she was someone who would one day climb all the way to the Tower's summit.
If she fled in fear now, what could she possibly accomplish going forward?
Iris raised her staff.
"Leon."
"Yes?"
"I'm sorry for misunderstanding you until now."
"You're apologizing all of a sudden?"
"In that spirit, let me show you."
Cold mana spread outward from beneath Iris's feet. A thin frost settled over the walls and floor.
"What a true elite's magic looks like."
Violet flames flickered inside the Lich's eye sockets.
"Interesting."
The creature raised its staff. Three necrotic bullets came flying from different directions.
"Ice Wall!"
A wall of ice blocked the first projectile. As the remaining two curved around it, freezing lances shot from the tip of Iris's staff.
Bang!
Both necrotic bullets vanished at once. While the explosion obscured the field of view, a third freezing lance punched through the Lich's shoulder.
A frost blade followed immediately after, slicing through its waist.
Crack!
The Lich's upper body toppled to the floor.
"Ohh."
Crunch — grind, grind!
The Lich, sprawled on the ground, calmly worked its jawbone.
"Not bad."
Iris did not answer.
She maintained the ice wall, shifted the coordinates of her freezing lances, and fed mana into the frost blades.
The moment the Lich began to regenerate, she froze even the surrounding bones to lock down its movement.
All of these processes were running simultaneously. The number of spell formulas Iris was processing in a single second exceeded ten. She had already left the realm of ordinary mages far behind — a true elite mage.
I can do this.
It was more manageable than she had expected.
Having imagined this battle dozens of times, she could win easily enough.
That was what she was thinking.
The Iris of this moment.
"Splendid."
Having gathered its scattered bones and restored its body, the Lich smiled.
"To possess this level of computational ability at your age."
Iris leveled her staff again.
"Indeed — you'll make an excellent head."
"…What?"
The Lich pressed its palm against the floor.
KRAAAAAA—!
Necrotic mana erupted on a scale incomparable to anything before.
"Ghk…!!"
Iris hastily raised an ice wall. But the wall, shoved by the wave of mana, slid backward intact.
"This much mana…!"
The Lich slowly rose to its feet. The robe covering its chest parted to either side.
"Did you know?"
Beneath the robe, a gaunt ribcage was revealed.
"I am not some corpse that happened to end up like this after dying."
"What are you…"
"I chose this body myself."
In life, the Lich had been a mage whose name alone was enough for anyone to recognize. He had devoted his entire existence to researching countless spells and devising countless formulas.
But a human had only one head. No matter how much knowledge one accumulated, there was a limit to the number of spell formulas that could be processed simultaneously.
"With a human body, I could never reach the realm I desired."
The violet flames flared wide.
"So with His aid, I transcended humanity."
The Lich spread its ribcage open.
Crrrrack—!
The nauseating sound of twisting bone echoed through the passage.
"That is…!"
Iris's voice trembled.
"Ugh, disgusting."
Leon grimaced.
Packed tightly between the ribs were ten different human skulls.
"You've been walking around with those stuffed inside your body? That's genuinely creepy."
"Creepy? Do you have any idea how exceptional these individuals were?"
The Lich spread both arms wide.
"Did you know? Every single one of them was a mage of considerable renown in life."
The skulls inside the ribcage opened their jaws.
Click.
Click-click.
Ten mouths began to move in different rhythms.
"I shall show you their power."
The Lich issued a single command.
"Attack."
Necrotic mana flooded into all ten skulls inside the ribcage at once.
Each skull took the received command and subdivided it into ten detailed calculations.
Determining coordinates, regulating output, computing range and trajectory.
Ten calculations processed by a single head.
And there were ten such heads in total.
"Kakakaka! This is the Multi-Chanting Spell — the technique that transcends the human body!!!"
Dozens of magic circles unfurled above the Lich's head. The ceiling, the floor, and both walls filled with violet patterns.
"It can process a full one hundred spell formulas per second!!!"
"One hundred… per second…?!"
Cold sweat ran down Iris's forehead.
The most she could process was ten. The figure Leon had handled when using the Continuous Trajectory Formula had been fifty per second. The Lich before her was operating nearly twice that many.
"…Leon."
"Yes?"
"Run."
"All of a sudden?"
"You can only use two kinds of magic! You can't block chanting on this scale!"
Iris stepped in front of Leon.
The number of magic circles the Lich was creating continued to grow. Whether she could block every attack, she did not know.
She might die here.
Even so, Leon had to live.
He had fallen to this place trying to save her. She could not let someone like that die here.
"And…"
Iris bit her lip.
"I'm sorry. For everything I've done until now."
"…"
"I'll hold it somehow. So in the meantime, hurry and—"
"This is a dead-end corridor. Where exactly am I supposed to run?"
"Ah."
A brief silence settled over them.
"I take it both of you are finished with your last words."
The Lich lowered its hand.
Dozens of magic circles blazed simultaneously.
Necrotic bullets, bone spears, and black flames flooded the passage all at once.
"Ice Wall!"
Three layers of ice wall surged up in front of Iris.
KRAAANG—!
The first wall collapsed immediately. Spiderweb cracks spread across the second, and a single necrotic bullet that punched through the final wall grazed Iris's shoulder.
"Ghk…!"
Iris fired a freezing lance at once. But a new barrier had already been raised in front of the Lich.
Bang!
The ice lance shattered uselessly.
In the time it took Iris to block one attack and counter, the Lich had already prepared both its defense and its next assault.
Between ten calculations per second and one hundred, there existed a gap as vast as heaven and earth.
"Did you truly believe a single human head could keep pace with my calculations?"
The Lich stretched a hand forward. Beyond the cracked ice wall, more than ten offensive spells took shape.
"I'll put your head to good use."
Violet magic circles lit the passage.
"Die."
Magic poured down.
…Is this how I die?
Iris gripped her staff.
At most, she could block four spells. The rest would get through.
…Father. Did I underestimate the Tower too much?
If she had been just a little more careful on the stone path, she might not have fallen. If she had checked the surroundings one more time after destroying the red core, the outcome might have been different.
She had been far too arrogant. Simply because she had graduated top of the magic academy, she had believed she could accomplish anything.
"…I'm truly sorry, Leon."
Iris murmured the words low, as if leaving a final message.
"Because of me… if it hadn't been for me, you never would have fallen here either."
"Yeah. That's true."
"…"
It was not the answer she had expected.
"Still, for last words, you could at least be a little kinder—"
Iris stopped mid-sentence and looked beside her. Leon was not even glancing at the magic flying toward them. Instead, he was scanning the magic circles spread through the air one by one.
"Yeah. So that's how it works."
Then, as if something had clicked into place, he gave a small nod.
"…Leon?"
"Ah. Now I get it completely."
Leon raised his right hand.
"Alright. Let's start with Mana Bullets."
A small light formed above his palm.
"What are you going to do with Mana Bull—"
Before Iris could finish, a second light rose.
Three.
Five.
Ten.
The lights did not stop multiplying.
Each projectile slowly orbited Leon at different heights and angles. And the total number was no less than—
"…Thirty?"
There was one more thing Iris had been mistaken about. The spell formulas Leon had calculated at the training grounds had numbered 52.7 per second.
A figure that already far surpassed the computational ability of an archmage. That was why Iris had roughly estimated Leon's calculation limit at fifty. But that had never been the AI's limit at all.
It had simply been that piercing eight targets only required that much calculation.
A human intuits a spell formula, imprints it in the mind, and computes it sequentially before casting magic.
But the Nano AI had no reason to follow human methods of calculation.
> [01110101101010111101101011000101]
It decomposed the observed flow of mana into the smallest possible signals.
> [10110011101001010110111010011100]
The positions of the magic circles the Lich had created.
The distinct mana flow of each spell formula.
The coordinates and velocities of thirty Mana Bullets.
The spacing required to keep them from colliding, and the trajectories needed to move to the next target.
In the span of a single blink, information far exceeding terabytes poured in, and those data soon swelled into the petabyte range — a thousand terabytes.
> Generating intercept trajectories.
> Excluding collision-risk paths.
> Incorporating real-time variables.
New calculations updated every time a new magic circle was formed.
> Generating intercept trajectories for each Mana Bullet.
> Excluding paths with mutual collision risk.
For every Mana Bullet, hundreds of thousands of paths were generated, possibilities compared, and unnecessary results discarded at once.
> Assigning targets to 30 Mana Bullets.
> Synchronizing individual coordinates and thrust.
> Initiating parallel control.
And when input, analysis, decomposition, and reconstruction were all complete—
> Constructing real-time intercept formulas.
> Applying real-time trajectory corrections.
> Intercept formula construction complete.
—the Nano AI, the concentrated essence of scientific technology, finally revealed its true performance.
Leon pointed a finger forward.
"Go."
Papapapapang—!
Thirty Mana Bullets scattered in every direction.
Necrotic bullets were pierced through. Bone spears and black flames detonated one after another.
Even newly unfurling magic circles had their cores punched out before they could complete.
In mere seconds.
The barrage the Lich had unleashed with one hundred spell formulas per second vanished without a trace.
The thirty Mana Bullets returned to Leon's side and slowly rotated.
"Controlling them is easier than I expected. Kinda feels like flying drones."
Iris could not comprehend the scene before her eyes.
"…Thirty Continuous Trajectory Formulas at the same time?"
Someone who had only been learning magic for three days was casually trampling the realm a Lich had abandoned its own flesh to reach. No — that was not a realm any living human being could attain in the first place.
"So it was true…?"
Iris's gaze locked onto the back of Leon's head.
"That a god dwells inside his mind…"
The Lich's reaction was even more severe.
"What…"
The skulls inside the ribcage all snapped their jaws shut at once. The violet flames that had been flickering in its eye sockets froze solid.
"What… is that?"
For the first time, the Lich took a step back.
"Just what in the world is thaaaaaat—!!!!!!!"
Leon looked at the Lich's face, contorted with shock, and said:
"? Mana Bullets."