Life is a book. A one-of-a-kind volume that opens with birth, ends with the full stop of death, and fills its pages with the passing years.

If life is a book, then my mind reading could be called reading. I can read surface thoughts by examining only the freshly written passages at the end, or flip through from beginning to end to get a rough idea of the contents.

I can also settle down and read every word from start to finish, but that takes a long time and puts me at risk, so let's skip that.

Amitengrad, the capital of the Military State, was a monster that had grown by devouring the surrounding cities. Its explosive growth pushed everything that had originally been there outward as it swelled.

People, houses, money—even ideas.

Everything pushed out had a story of its own. Having lived among them, I prided myself on having encountered a fairly wide variety of people.

But above every runner is someone who can fly, and beneath rock bottom is another depth dug an inch deeper. As befitted the great prison the Military State took such pride in, the inhabitants of Tantalus were on another level.

The King of Dogs.

The vampire Progenitor.

The Regressor.

Monsters who could lay waste to an entire city if set loose. Their books, too, followed an entirely different course, as though insisting that their owners defied all standards.

To describe Azi's book, it was like a phonetic transcription of a cave painting written in ancient hieroglyphs. I could read it, but I couldn't understand what it meant.

What this was, what that was. Why left and right needed separate names to tell them apart. Why someone with a ball wasn't throwing it. Azi's book lacked even those concepts and made no attempt to understand them. Nor did it try to explain. As though that were perfectly natural.

In a way, it was. There was no reason a dog and a human would follow the same logic in their thinking. As long as I was human, the day would never come when I fully understood Azi's book.

If I read her thoughts carefully, I could at least work out how she felt, but at that point I might as well lift my head and read her expression. There wouldn't be much difference between reading her thoughts and reading her face.

The vampire's book could be summed up in one word: thick. Befitting an ancient monster who had lived for over 1,200 years, it weighed down on me with twenty times as many pages as an ordinary human's. Even a casual skim required mental preparation.

It would be one thing if there weren't much in it, but her life had been so tumultuous that she'd practically written a grand epic. Her awakening as a vampire, a history of humiliation and persecution, long years of struggle, reign and downfall, flight and eternal slumber... That was just what I'd caught while flipping through, so I couldn't begin to bring myself to tackle it. The way it reflected the eras she had lived through made it difficult to understand, too.

A scholar of ancient literature would have fallen in love with that book. Unfortunately, I was the only person who could read the books of the mind.

And I wasn't a scholar of ancient literature.

Last, the Regressor.

Her book didn't fit into any category. If I had to describe it, it was something that could never exist, and should never exist... a fourteen-volume series.

A life that kept going as though cheating, even after its final full stop. Even after reaching an ending of its own, however miserable. An interminable story dragged out by an author who couldn't let go. One that showed no sign of ending, either...

That put me in a very awkward position.

I had clearly read it, but I couldn't understand it.

She was living this life, but her guiding principles, beliefs, experience, abilities, and equipment had all come from previous lives. The reasons behind her actions, the enemies she had to defeat, and the events that had happened in the future were recorded in earlier volumes.

Unlike the Regressor, however, I had no magnificent ability to transcend time. All I could read was the story of this timeline.

To extend the analogy, it was like picking up the newest release after skipping volumes one through thirteen. I couldn't follow the story or understand why she was doing what she was doing.

So although I had learned that I would die and the world would be destroyed in the future, I hadn't been able to read how any of it happened. All I could do was infer things from the memories she occasionally recalled and the actions she took.

To find out, I would have to hear it directly from the Regressor...

Or make her 'reminisce' about the past.

"Ugh. Either way, I'll have to deal with the Regressor in the end..."

Realizing my predicament, I heaved a sigh deep enough to sink the ground beneath me.

Not that there was any farther for it to sink in a bottomless pit.

In a prison with no entertainment, you naturally end up in the yard when you have nothing to do. I opened the barred front gate and stepped outside.

An utterly bizarre sight greeted me.

"Tyrkanzyaka! I've come to see you! Open the door!"

The Regressor stood in front of the underground armory, shouting with both arms spread wide.

The underground armory. A place stocked with weapons for forcibly suppressing prisoners should they riot. It was built from alchemical steel of at least level 3, and opening the door required passing through three security procedures.

At Tantalus, however, where all the prisoners were beyond anyone's ability to handle, they apparently put 'something else' inside instead of weapons from the outset. In a way, it could be called the ultimate weapon. In any case, it remained an area ordinary prisoners were absolutely forbidden to approach. Anyone who wandered up without knowing better would have no grounds to complain if they were executed, whatever their reason.

Right in front of that underground armory, where prisoners weren't allowed, the Regressor was performing something resembling a ritual.

What on earth was she doing? I watched her for a while before suddenly remembering that I was impersonating an Instructor.

Hmm. If I was an Instructor, did that mean I had to stop a trainee snooping around the underground armory? I didn't want my head cut off for interfering.

The Regressor was a terrorist holding the whole world hostage. No, a mad scientist running repeated experiments on the entire world. An irresponsible brat who would scrap this entire run and move on to the next if things went wrong.

But failing to play my role would only make her more suspicious. She was a Regressor repeating her lives in search of the best possible future. If she decided I was an anomaly, neither Instructor nor prisoner, she might try even harder to eliminate me.

Fine. I'd stop her. Surely she wouldn't actually kill me.

I shouted in a deliberately angry voice.

"Trainee Shei! What are you—!"

'Tch. Here comes a nuisance. But I can't let anyone interfere now. If he gets in my way, I'll have to get rid of him somehow...'

"...doing up so early? Did you sleep well? Good morning. This was my first time sleeping in prison, but sleep is sleep, whether you're inside or out."

Barely stopping myself from delivering a scolding, I changed my expression and approached with a bright smile.

To think she'd actually consider killing me. All right, that settled it. From now on, I'd let her do whatever she wanted.

"... Tch."

As I watched her with an easy smile, the Regressor scowled, whipped her head away, and ignored me. Still, she apparently had enough decency not to spit in a smiling face.

Yes. Thank you. Nice to see you, too.

After exchanging greetings all by myself, I walked toward the firmly shut armory door.

"Shouting at the top of your lungs in broad daylight. What exactly are you doing?"

"None of your business."

"Are you trying to meet the person inside?"

The Regressor gave a short click of her tongue. Apparently, clicking her tongue was how she said yes.

"Why are you trying to wake someone who's sleeping soundly?"

"I said it's none of your business."

"Honestly. Can't I say anything?"

The Regressor was so wary of me that she refused to do anything in front of me. It was a real problem.

How had the world approached its destruction? What had happened here? Only the Regressor could answer my questions. To get those answers, I needed her to reminisce about the past in my presence.

But with her current attitude, I could spend a year trying and still have no hope of digging up events from her previous run—which, to me, were events in the future.

Hmm. What to do? I cast my gaze toward the underground armory.

There were no weapons in Tantalus's underground armory. Unlike ordinary prisons, the great prison of Tantalus was an isolated space impossible to escape by conventional means. With no fear of prisoners running away, they had stationed neither Instructors nor weapons to attack prisoners in an emergency.

Instead, they had put something else inside.

The first vampire, the heaven-defying monster, the Queen of Darkness.

Progenitor Tyrkanzyaka.

It served as both palace and prison for a vampire who shunned the light and hid underground.

And the Regressor was trying to awaken that ancient vampire, Progenitor Tyrkanzyaka.

From my perspective, waking a being whose staple diet was human blood wasn't particularly pleasant. Especially now, when I was the only proper human around.

But I needed to get the Regressor talking. Helping her with a little task like this should move our relationship forward.

What should I do?

My deliberation was brief, my decision quick. Fine. I'd help her.

Surely the vampire wouldn't kill me? With most of the prisoners gone, I was the only 'ordinary' human left in Tantalus. To a vampire, I was a precious resource producing blood day after day. Surely she wouldn't kill the goose that laid the golden eggs just to quench a momentary thirst. At worst, she'd leave me neither dead nor alive and drain my blood for all eternity.

... What a bleak future. Still, it was better than dying.

Having made up my mind, I offered the Regressor a suggestion.

"Why not just break down the door?"

"This door is under Tyrkanzyaka's control."

I looked where she pointed. A bloodstain glimmered red in the keyhole where the security mechanism should have been. I had no eyes for reading energy, but even I could tell the pattern was brimming with something ominous.

"The Blood Sigil. As long as it shines with that ominous light and exerts its control, this iron door, reinforced with her blood, is no different from one of Tyrkanzyaka's familiars. It will never open without her command."

"I'll look the other way, so try breaking it with everything you've got. Who knows? Hammer away for a few days, and it might crack."

"... It's not impossible, but I don't want to. I'm here to ask Tyrkanzyaka for help, not fight her."

Huh? I'd just thrown that out there. Why was she saying it wasn't impossible?

An ordinary human couldn't cut through a solid steel door. And this one was made of the Military State's special alchemical steel, with level 3 strength. You couldn't break it by ramming it with a carriage or firing a cannon at point-blank range.

She could break that just by giving it her 'all'? Come on. It shouldn't break just because one human tried their hardest. That was the least it owed the person who made it.

"You're more reasonable than I expected."

"Obviously. Killing someone's familiar is even ruder than breaking down their front door."

"Honestly. The person who tried to chop off my arm out of nowhere is lecturing me on manners."

"What?"

"Nothing. Just talking to myself."

I looked away from the Regressor's glare and sank into thought.

The alchemical steel used in a standard underground bunker was level 3. Hmm. If I used 'that,' it might just work. Should I try?

I rummaged through my pocket and took out the bell. The very same one I'd used to train Azi yesterday.

"What's that bell for?"

"It's a dog-summoning bell."

"A dog-what?"

It was only a small chime bell, so it wasn't particularly loud, but Tantalus was far too cramped for a Beast King whose home was the entire world. With Azi's keen hearing and sense of smell, she would hear it as clearly as if it rang beside her ear.

Normally, of course, she would have ignored it even if she heard it, no matter how much I rang. There were too many sounds in the world to pay attention to every little noise.

But after spending all yesterday with this sound, she would definitely come when she heard it. That was why I'd kept ringing it, over and over, while playing with her. I raised the bell above my head and shook it.

JINGLE, JINGLE.

"Woof? Woof!"

As the little bell rang clear, barking came from far away. A moment later, Azi began running down the wall from the building's roof.

No joke—she really was running down the wall. Several times faster than she would have fallen. The gray-white concrete of the outer wall chipped away under her feet, leaving canine tracks. She landed with a thud, then sprang into a furious charge toward me before I could even feel the vibration.

It was a sudden, violent change of direction, like a rubber ball bouncing off the ground. Faster than free fall. Getting hit by her would easily kill a person.

I frantically searched for the pieces of meat I'd prepared yesterday. Barely managing to pull one out before Azi reached me, I hurled it straight at the underground armory door.

Azi raced past me after the meat.

And slammed into the iron door without slowing down.

BOOOOM.

A grand, magnificent sound rang out. Even striking a huge bell in a bell tower wouldn't have been louder. I could feel the air of Tantalus trembling against my body, as though I were inside a percussion instrument. It was probably my imagination, but the impact seemed to have tilted the ground a little.

Horrified, the Regressor seized me by the collar.

"You...! What the hell are you doing?!"

"Now, now. Just watch."

"I told you! I need Tyrkanzyaka's help!"

"What can I do? My dog ran into it."

Meanwhile, Azi, the source of that impact...

"Yummy! Woof! Yummy!"

...stood utterly unperturbed, the meat in her mouth and a blissful expression on her face.

I looked from Azi to the iron door and nodded.

"Hmm. That should have easily shattered level 3 alchemical steel. The sigil's reinforcement must be stronger than I expected. Level 4 at least."

Even after Azi had rammed it at full speed, all she had left were footprints. If she flew into a rage and unleashed a Serious Woof-Woof Punch, she might get through, but the gentle King of Dogs was hardly going to get angry at an iron door.

Fine. Now that I'd confirmed it wouldn't work, I didn't need Azi anymore.

"You came when you heard the bell. Good girl. Now, off you go."

"Awooo!"

Azi shook her head vigorously and bounced around beside me, her tail whirling in circles.

"Let's play! Woof! Let's play!"

"We played yesterday."

"So let's play!"

Yesterday was yesterday, and today was today. What a forward-looking beast, unconcerned with such things as the past.

"I'm busy today. I'm not playing. Go back."

"No! Let's play!"

Looking disgruntled, Azi pretended to bite my calf. Ugh. So stubborn. Did she think I was her servant?

This was all the Regressor's fault. I should have straightened her out yesterday, but the Regressor had interfered with her insistence on watching me, leaving me to give Azi nothing but carrots without using the stick. I shot her a resentful glare.

"Wh-what? Why are you looking at me?"

"Sigh. Forget it."

So irresponsible, all of them. Not one of these advocates for dogs' rights ever took proper responsibility. They put the dog on a pedestal, and I was the one left playing with her.

But unlike beasts, humans were animals that reflected on the past. I'd made preparations for precisely this situation before coming outside. I wasn't going to become a ball-throwing machine like yesterday.

"Here, Azi. Smell my hand."

"Woof!"

As soon as I held it out, Azi pressed her nose against it and sniffed. I alternated between my palm and the back of my hand so she would remember my scent properly. Once enough time had passed, I pointed toward the prison.

"Oh no! Azi, we have a problem. I left the ball inside."

"Woof?"

"You remember my scent, right? Follow it and bring the ball back for me. Then I'll play with you."

"Woof, woof!"

Without the slightest suspicion, Azi kicked off the ground and raced into the building. I smiled triumphantly as I watched her go.

Heh heh. In preparation for today, I'd washed the ball thoroughly and shoved it deep beneath a pile of collapsed concrete. Even the King of Dogs would take ages to find it.

That bought me some time. I turned toward the Regressor.

"It seems there's a limit to what ramming can accomplish. Now, shall we find another way?"

Huh. There was that look again. That expression of displeasure at how I handled the puppy.

The Regressor glanced at the departing Azi and spoke with a sour expression.

"... When did you get so close to Azi?"

"Close? All I did was play with her for a day."

"That's impossible. I've been here over a week, and she barely acknowledges me..."

That was because you treated a dog like a human. You could wave at a dog all day and say, "Hello, lovely weather, isn't it?" and it would be nothing but meaningless barking. You had to train her with carrot and stick, like me.

Well, enough chitchat. Time to get back to figuring out how to enter the underground bunker where the vampire lived.

"Anyway, if even a dog missile can't open it, and you don't want to smash it... we'll have to get her to open it herself from inside."

"I've tried everything. Shouting, knocking. But Tyrkanzyaka hasn't shown any response."

"Haha. Don't worry. I know how."

"You do?"

The Regressor raised her eyes suspiciously. Leaving her behind me, I sank into thought.

When I'd first fallen into Tantalus, the vampire had awakened, if only very briefly. I'd definitely caught a faint trace of her thoughts then.

Why had she woken up? To welcome a newly arrived prisoner? No, she wasn't that sort of person.

Then there was only one reason.

"We need to offer blood."

When Azi had bitten my ankle and dragged me, I'd fallen and scraped my skin, drawing blood. As naturally as water flowing downhill or a ripe apple falling to the ground, the vampire had exerted her dominion over my blood and absorbed the drops pooled on the concrete.

And then what? Hadn't she complained that it tasted bad? Thinking about it again annoyed me. She was the one who'd helped herself.

Whether she'd woken because it tasted bad or for some other reason, she had woken in response to blood.

"An offering of blood will wake the vampire."

I declared it proudly, but the Regressor snorted and held out her finger.

"You think I couldn't work that much out? I've already tried."

Her fingertip was pale and soft, since she hadn't wielded a sword much 'yet.' A thin cut there had begun to heal.

"I cut my finger and offered blood. But Tyrkanzyaka didn't wake up. The blood just got sucked inside."

"Huh."

"Hmph. You sounded so smug, but you don't have any real ideas either, do you?"

The Regressor folded her arms and taunted me. My failure seemed to have cheered her up. Hey, why was she happy that the plan I'd worked to come up with had gone to waste?

Given that the spilled blood had been drawn inside, she could definitely 'sense' it. But shedding a little blood wasn't enough to wake her. Absorbing blood was as routine to a vampire as breathing.

Hmm. Then there was only one thing left to try.

"Let's write in blood."

"What?"

Originally, the ringing of a bell had been nothing but meaningless noise to the King of Dogs—metal striking metal. Until then, it had stirred no feelings in Azi.

But after I played fetch with her and gave her a treat whenever the bell rang, its sound finally took on meaning. A clear chime that evoked pleasant feelings.

That was the poetic explanation. Less romantically, it was called learning.

The same applied to the vampire. A simple bloodstain would get sucked up, but if we wrote something in blood, her awareness would surely turn toward it.

"It seems certain that Trainee Tyrkanzyaka can sense blood. But with no meaning behind it, she simply absorbs it without thinking. If we could convey a message by writing in blood... at the very least, we'd find out whether she wants to meet us, wouldn't we?"

"... Tch."

'That... makes sense. He's got a decent head on his shoulders. I'll give him that.'

If she was going to acknowledge me, I wished she'd say so aloud. Instead of clicking her tongue.

"Fine. I'll try it."

The Regressor reached behind her head and grasped empty air. Only then did the image of Sky Cherry Blossom, the sword of the sky hovering behind her head, enter her awareness. I'd wondered where she'd put her weapon. She'd been keeping it afloat with her energy arts and simply leaving it there.

It was so completely unconscious that even my mind reading hadn't caught it. I'd thought she was unarmed, but she'd had a sword floating over her head? Weightless as Sky Cherry Blossom was, that made it all the more demanding to control precisely.

That wasn't a level of skill talent alone could achieve. It was an art ingrained in the body, attainable only by someone who had carried the same sword for years, even decades. I was reminded anew that the Regressor had far more experience than she appeared to. Just how many runs had she carried that sword through to keep it afloat without even thinking?

I'd have to be careful from now on. Her weapon was closer than it looked.

It was just as that thought crossed my mind.

SNICK.

The sword swept horizontally. Her finger lay in its path. With near-masterful precision, the Regressor sliced into her own finger without severing it, then left Sky Cherry Blossom floating and raised her hand.

A cut too fine to see marked the long, pale finger, and bright red blood welled through it.

Then blood poured out as though someone had turned on a tap. Enough to make me worry about anemia.

It hurt just to look at, yet strangely, I felt calm, as though my mind had settled.

Perhaps because the Regressor herself felt no pain at all. Drawn into that peculiar composure, I could only stand quietly.

"What should I write?"

The Regressor held her bleeding finger upright like a brush. The blood dripping from its tip stood out vividly. I cleared my throat softly and answered.

"All right, write this. 'Ven.'"

"'Ven.'"

She began to write, taking care not to let the falling blood spoil the strokes.

"'Er.'"

"'Vener.'"

"'Able elder.'"

"'Venerable... elder...'"

Having written that much, the Regressor suddenly jerked her head up and exclaimed,

"Venerable elder?"

"Yes. 'Venerable elder, it is time for you to rise.' Let's write that."

"Wait! What the hell are you doing?"

"What do you mean? I'm quite literally trying to wake an elder."

Apparently, the Regressor didn't know much about Progenitor Tyrkanzyaka. They must not have had much to do with each other in her previous runs. I calmly explained for her benefit.

"Trainee Tyrkanzyaka is an elder of no less than twelve hundred years, and in her heyday, seniority ruled everything. So it's only appropriate to use the most polite, respectful form of address possible."

"No, it isn't! Even so, what woman in the world likes being treated as an old lady?!"

Oh, come on. After twelve hundred years, you weren't an old lady—you were a history book. She'd been alive longer than most countries. Surely someone like that knew her own objective age.

That was when it happened.

["What impudent whelps..."]

A deep, dark voice sounded, and the underground armory's iron door slowly opened with a smooth metallic sound. Through the widening gap, pitch-black darkness roiled within.

Most of the light illuminating Tantalus in the bottomless pit came from searchlights. Their sharp, tightly focused beams made shadowed areas all the darker.

But... the darkness in the underground armory was something entirely different from a mere absence of light.

A blackness that seemed to devour light. Yet a blood-red hue shimmered within that unlit darkness. Unmistakably pitch-black, yet red as blood. A contradiction beyond common sense.

But the being dwelling within was a monster that shattered the measure of common sense.

Days,

Months,

Years,

Centuries...

The blood-price of humans who had faded into legend, history, and the passing eras. A history of blood that had reaped all those deaths, ruthlessly compressed and condensed, surged down below.

What stood before me was surely a mystery beyond any discussion of strength or weakness.

One spoken of in fairy tales, occupying a page of history, passed down as legend.

Progenitor Tyrkanzyaka.

A chill crawled over my skin. Inside was a monster that had lived for a thousand years on human blood. A heaven-defying darkness that had waged war against the entire Holy See alone.

Just as I began to fear that undoing the seal had been a mistake...

["Enter."]

The sturdy iron door swung wide, and the blood sigil, glowing bright red, looked down upon the Regressor and me.