Death is often depicted as having no feet. Wherever people hid, however far they fled, it followed close behind, and even those who constantly guarded against it succumbed without noticing its approach.

But Lieutenant Colonel Callis's death was most certainly walking on two feet.

A boy pretty enough to be mistaken for a girl approached with clear intent to kill—and the ability to do so. With every step he took toward Callis, she drew closer to death.

Her survival instincts sounded a warning.

“Wh-what are you doing? As the Instructor of Tantalus, I was dealing with a trainee who refused to obey orders...”

Though she knew it would do no good, the officer stammered out an excuse to the approaching Regressor.

Naturally, it did no good.

“Actually, you don't have to let go. You're going to die anyway.”

Refusing to let go because of those words would only seal her own fate.

The officer flung the chain away and backed off in faltering steps. It fell to the floor with a clatter, and Azi opened her eyes a little. The chain was still wrapped around her neck, but she paid it little mind. A tug on a chain couldn't hurt her anyway.

She merely watched the humans fighting one another with a little sadness.

Sensing that the smell of blood would soon fill the air, Azi turned toward the darkness.

In contrast, the undying one, who had no fear of death, boldly faced death's approach.

“Well, if it isn't the boy with that scandalous taste for men! Unfortunately, the lieutenant colonel is a woman! Her manner is so stiff that you must have mistaken her!”

It was a frivolous joke, but it had no effect on the Regressor now. Once that switch had flipped, nothing remained in her heart but killing intent honed to a razor's edge.

Nor was it an intent that could be satisfied with death in this life alone.

It was a will to annihilate from a more fundamental, transcendent perspective... to strip someone of existence in every possible future.

“... Must you really do this, boy?”

Even the undying one, who never experienced death, could not smile before a presence that went beyond murderous intent. He watched the Regressor, his body drawn taut, ready to spring at any moment.

Now twenty paces separated them. The Regressor addressed the man blocking her path with evident annoyance.

“You were better off with your limbs detached. At least you weren't in the way then.”

“And you were better when you were flustered and fumbling, boy. You were quite human then. Now you're truly... a demon of slaughter.”

The undying one gave a hollow laugh. Not out of composure, but because he had realized the gulf between them.

Even this close, she did not slow.

Despite her ability to launch blades of wind, despite being able to rain down deadly attacks from this distance, the Regressor never slackened her pace. As though the likes of the undying one did not even constitute an obstacle.

Step by step, she drew closer, neither slowly nor quickly. Steadily, like an appointed hour approaching with every passing moment.

If she reached the officer like this, as the woman trembled in the grip of her killing intent...

The undying one murmured, “Callis. Run.”

This was the bottomless pit. The ultimate dead end, with nowhere to flee in any direction.

Even knowing that, he could do nothing but say it.

“Anywhere! Hurry!”

Coming to her senses, the officer nodded and immediately ran. Her frantic footsteps echoed.

Watching her retreating back, the Regressor murmured, “Just as I thought. You're better off not existing.”

The Regressor drew back her arm. That simple motion sucked all the wind filling the corridor into a single point.

The last trace of amusement vanished from the undying one's face, and he shouted with desperate urgency.

“Run, now—!”

An instant later, the Regressor aimed at the middle of the officer's back and thrust Sky Cherry Blossom forward.

Heavenly Sword Art, Sunshot.

A single stream of wind blew. Compared with the tremendous buildup, the result seemed utterly insignificant. A small, soft sound drifted down the corridor, like someone blowing a puff of air.

But its power was far too ferocious to dismiss.

“Hah!”

The undying one immediately moved into the path of the Regressor's sword tip. As expected, invisible sword energy pierced his body. Through his crossed arms, his muscles, his bones, his air-filled lungs, and out through the skin of his back, all in a single instant.

His expression turned troubled. Its penetrating force far exceeded his expectations. It was overwhelming power, impossible to stop merely by crossing his arms and throwing himself in its path.

“Duck!”

Shouting, the undying one twisted his body.

The sword wind pierced through him and swept past the officer's cap. That symbol of the Military State's authority went spinning through the air. Staggering from the impact, the officer barely regained her balance before fleeing up the stairs.

The Regressor clicked her tongue.

“Tch. You managed to twist your body even then?”

“Haha! Quite the stunt, wasn't it? Still, it worked!”

As the sword wind passed through him, the undying one had tensed every muscle and twisted. Since it was piercing his body at that very moment, it was as though he had seized it with his entire body. Thus even the sword energy said to shoot down the sun was knocked off course, grazing above the officer's shoulder instead of striking her neck.

Although she had failed to kill her, the Regressor felt no particular regret.

“You've only bought her a moment. This is the bottomless pit. No one can escape from here. The lieutenant colonel is going to die.”

“Haha. Take it easy, boy. She was merely feeling a little cornered.”

“Being cornered brought out her true nature.”

“There is more than one side to a person's nature, boy. Everyone has good and bad within them, existing together like two sides of a coin. Here in this dark, lightless land cursed by Mother Earth, her bad side simply stood out!”

“Yes. I understand.”

The Regressor gave a small nod and added, “Then I'll kill the bad part. You can deal with the good part yourself... if it's still alive.”

It seemed no one could persuade the Regressor. It seemed no one could even stop her. Her anger also had a valid cause, so she herself had no intention of stopping.

At a loss, the undying one spoke.

“Must you spill blood, boy?”

Seeing her expression grow colder, he hastily added, “Ah, don't misunderstand! My blood, of course!”

“What about you? Do you have a reason to protect the lieutenant colonel even at the cost of your own blood?”

“Of course. She's my friend!”

The undying one declared it boldly, without a moment's hesitation. The Regressor swept back her hair in annoyance and spoke.

“I wasn't going to say this because it would sound like I was demanding gratitude, but this is going to get annoying if it keeps up. It wasn't the lieutenant colonel who revived you. It was me. I shoved your cursed, sickly right arm into a healing potion made with a World Tree leaf and regenerated it. The lieutenant colonel only looked like she'd saved you by pure coincidence...”

“Haha! I know! My right arm told me! You have my heartfelt thanks for that, boy!”

“... Then why?”

The undying one answered readily.

“Regardless, she came intending to help me, and she had the means to do it! Even if my right arm hadn't arrived just then, the lieutenant colonel would have helped me! Well, doesn't that make her a friend?”

“Haah. Fine. I get it.”

With a deep sigh, the Regressor resumed walking, Sky Cherry Blossom in hand. Stretching his right foot far behind him, the undying one cried out boldly.

“Of course, I consider you my benefactor too, boy! I have no wish to be your enemy! Ah! I'm not just saying that to soften the blow because I think I'll lose!”

“Tch. Of all people, it had to be someone undying. I can't even kill you... Better to blow you away and move on. Phew.”

“I may not be able to stop you, but I won't let you pass easily!”

Seeing the Regressor raise her hand, the undying one let out a wild cry and charged her.

Not to attack, but to shorten the time her blades spent tearing through his body. The farther he retreated, the longer he would be ravaged. He resembled light infantry running head-on into a charge of heavily armored cavalry.

In any event, he met much the same fate. As the violent wind swept past, his sturdy body fell apart in an instant.

Literally.

* * *

'Escape. I have to escape.'

The Progenitor was indifferent to humans. The dangerous individual was currently getting along with the convict laborer without any particular trouble. The undying one's limbs had been torn off, and the target, the King of Dogs, was friendly toward humans.

That was why Lieutenant Colonel Callis had judged the mission would be easier than expected. All she had to do was enter a bottomless pit full of beings who cared nothing for people and secure the King of Dogs. Unless something dramatic happened, Callis, too, would be safe.

The convict laborer's brazen survival to this day was proof—or so she had thought, making the most terrible mistake of all.

'I was wrong. The moment I touched the King of Dogs, they all reacted.'

The convict laborer had interfered the moment Callis approached the King of Dogs.

The Progenitor protected him with all her might and was even willing to make an enemy of the nation for his sake.

When Callis approached the King of Dogs behind their backs and placed a “chain” around her neck, the dangerous individual flew into a rage and came at her with intent to kill.

'Everyone here is an enemy.'

That was devastating news for the Lords of Creation. They had planned the operation as though they were merely picking up an abandoned object, when in reality it was about as difficult as walking into hell and stealing the treasure of the king of the underworld.

'Have they grown attached? Or have they discovered who we are and decided to interfere? Whatever the case, I have to tell them. The operation must be canceled. And...'

That circumstances made the mission impossible, and she would escape to save her life.

Abandoning a mission midway was unacceptable, but surely even they did not expect Callis to succeed amid this hell. Better to live to try again than throw away her life.

Callis reached the fourth floor, gasping for breath. A soldier of the Military State would not be winded merely by running up stairs, but her body, which had just experienced a brush with death, desperately sought proof of life through its ragged breathing.

Red hair clung to her face. Only then did she realize the cap that always held it down was gone. Its absence made her uneasy for no reason, but she should be grateful her head was still attached.

Callis opened a concealed compartment in her belt and took out a bundle.

'For communication.'

The Military State's synchronized-type magic golem was the invention of the century, but no one could resonate with it without a particular Unique magic. To send messages, ordinary people had to use communications facilities or fall back on more primitive methods.

Like the brooch set with four gems that Callis now held.

'Break one for safe, two for caution. Three for danger... And breaking all four means everyone present is completely hostile.'

Twin gems created through a special alchemical process were designed so that when one broke, its counterpart would break as well.

They could only be used once and were useless unless signals were agreed upon in advance, but the secret society known as the Lords of Creation made full use of those very properties.

'I have to assume even the Progenitor is hostile to us. Four gems must be broken.'

Callis pulled back the pin attached to the brooch. Strangely, a heavy iron ball sat at the tip where a sharp point should have been. When she pulled it back as far as it would go and released it, the ball sprang forward and struck the red gem.

The shattering of the gem rang down the corridor.

'They told me to make sure I broke the gems before escaping. That way, those above could prepare an escape route.'

One, two, three, four. The sounds of shattering gems rang out in succession.

Having broken every gem and finished sending her message, Callis took out the final bundle, the one meant for escape. It was sealed more tightly than the others. Her nervous fingers kept slipping, but she scratched at the knots again and again with her nails.

That was when it happened.

『Loyalty. Lieutenant Colonel Callis. This is communications officer Captain AB.』

A tiny golem walked out of the dining hall. It was the communications officer's synchronized-type magic golem.

The unfamiliar voice startled Callis, but her face brightened as soon as she recognized its source.

“Captain!”

She had needed to keep the communications officer at a distance to conceal her activities as a member of the Lords of Creation. Those had been her instructions as well.

But now that she was trying to escape, even a communications officer was a valuable ally. Her only ally who could relay the situation outside.

“Good timing. I intend to leave Tantalus. The trainees here are still far too violent for resocialization. Captain, help me...”

But the golem's message cut her short.

『... The military authorities have approved the temporary suspension of your authority, Lieutenant Colonel Callis.』

“What?”

She was so shocked that her hands briefly stopped undoing the escape bundle, her very lifeline. In contrast, the communications officer's voice remained flat and dry.

『You reportedly entered Tantalus due to an error, but that nevertheless constitutes a failure on your part. The military authorities have decided to impose disciplinary action for that failure.』

Disciplinary action. Even with her life in danger, those words delivered a different kind of shock to Callis.

The Military State's screening was strict. To attain Level 4, she could not have a single disqualifying mark. Having no failures was even more important than earning distinctions.

And now, disciplinary action? Callis protested.

“What—what do you mean? Didn't you say there was a problem with the written orders? The orders I received told me to supervise the supply process!”

『That is correct. However, the bottomless pit is a Level 5 secure facility. Even if you were following orders, your decision to enter Tantalus without any verification inevitably raises questions.』

“I can explain. I can explain that.”

Callis spoke urgently, but the answer from the golem was almost cruelly rigid.

『I merely relay this information and exercise no influence over the decision-making process. I recommend that you present your explanation to the investigation team when it arrives. That will be all.』

As though there was nothing more to say, the golem gave a brief salute and returned to the dining hall. The strength drained from Callis's body.

How could this happen? What had she risked her life to come here for? The dream that had brought her here was about to vanish as nothing more than a dream.

'No. I just have to escape.'

The Lords of Creation had branches throughout the Military State. With roots everywhere from the military to the civil administration, they would resolve this problem if she could only return. All she had to do was escape.

Callis clenched her teeth and worked at the tightly tied knots.

At last, the troublesome knot came loose. She hurriedly opened the bundle and looked inside.

It held a packet with geometric figures drawn on its hard, rectangular casing.

'An equipment packet!'

Equipment packets were alchemical weapons that produced simply constructed equipment such as daggers and shields.

This packet must be her means of escape. Callis immediately opened her biometric terminal and inserted it. The packet flowed along the Arche Avatar enveloping her entire body and began taking shape near her shoulder.

'How do I use this? Is there another message?'

Just as Callis peered inside the bundle for another clue,

a blade that had sprouted backward grazed her neck.