Defining the Relationship (2)

Master to a Hero.

Strictly speaking, I could have chosen a far more fitting label: the Hero's guardian. Yet I had deliberately settled on "master," and for good reason.

Left as she is, she won't live long.

Hero. Test subject. Esper. Chimera. Astrea was saddled with far more labels than any single person could bear. While my grasp of medicine and esper abilities was hardly on the level of a licensed doctor or a coalition researcher, I could comfortably pride myself on being something of a specialist. And viewed through that experienced lens, Astrea's condition was unequivocally dire.

The multitude of foreign esper abilities crammed into her body were violently clashing against one another, tearing her apart from the inside, while her innate cellular regeneration—far from being properly utilized—was burning away haphazardly just trying to keep her alive. In short, her vessel was overflowing with far more power than it was ever meant to hold.

Those who obtain power beyond their vessel rarely meet a pleasant end.

Astrea would be no exception. An esper ability used improperly—or running rampant—was far worse than having none at all. That didn't mean keeping her locked in this endless loop of sleep, eat, and sleep while blindly suppressing her power was a viable solution either. Once conflicting abilities began tearing into each other, they wouldn't miraculously settle down just because you left them alone. More often than not, leaving them unattended led to outright neglect, allowing the wounds to fester into something far worse.

I knew that better than anyone—because I had lived it. Even now, cold sweat broke out on the back of my neck whenever I recalled the time I absorbed an esper ability without understanding it and nearly died in my sleep. In any case, going by my own experience, leaving Astrea as she was meant an early grave. If luck ran completely against her, shock could kill her within a day or two. Being chosen as a Hero granted her Causality Correction, which kept her stable for the moment, but it took no genius to see that once that correction wore off or enough time passed, she would be in lethal danger.

"I didn't go through the trouble of saving her just to let her rot away and die."

Besides, considering Astrea's background, building up her strength was an absolute necessity. Who could guarantee that the Humanity Coalition—who kidnapped innocent people just to burn through them as guinea pigs—wouldn't come back to drag her away? If she couldn't stop them from recapturing her, she was doomed to be used as a living weapon of war or thrown straight back into the vivisection labs. As she was now, Astrea was merely a frail girl with quick cellular regeneration and a slightly sturdier frame; fighting back wouldn't even be an option. To prepare for the worst, she needed to learn. ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠Whether it was combat techniques or esper control, she had to master something.

To boil down a long story: my objective was to play the master, teach her how to wield her esper abilities, and ensure she could survive without coming to harm.

Well, maybe I have a little ulterior motive of my own.

If I trained her well enough, she might eventually lend a hand when it came time to subjugate the Main Gate—though, realistically speaking, that was just wishful thinking and pure fantasy on my part, best set aside for now.

"Well then—"

Time to go make the pitch.

Basking in the morning light that crept over the horizon, I made my way toward the room where Astrea lay asleep.

"...Could you explain that one more time?"

"Sure. That ability belongs to the category that forcibly accelerates your physical reaction time—"

Ordinarily, the hideout was swallowed in heavy silence, but today there was no trace of stillness. Sharp concussions—halfway between striking impacts and sonic cracks—echoed in rapid succession, punctuated by the steady cadence of conversation.

"Right, exactly like that. It stimulates the nervous system, so that's the proper way to trigger it."

The source of the commotion was the open clearing directly in front of the hideout. Ever since the day Astrea crash-landed, my daily routine of clearing rubble and sweeping the surrounding city ruins had left the grounds as immaculate as an athletic field. With only a slight exaggeration, you could call it a sprawling wasteland paved smooth. And right in the middle of that clearing stood Astrea and me.

"Ready?"

"...Yes."

"Here I come."

*BOOM—!*

The instant our brief ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠exchange concluded, a deafening crack ripped through the courtyard. A sonic boom, to be precise. It was the natural result when the simple motion of throwing a punch crossed the threshold of supersonic speed. Naturally, I was the one throwing it, and my target was Astrea's left arm. It was a strike launched at a velocity far beyond the reflexes of any mundane human, and faster than what the vast majority of espers could track. By all rights, the punch should have not only connected with her left arm but blown it clean off her shoulder. And yet...

"...Did I pass?"

Astrea had miraculously dodged my fist by a hair's breadth.

"Yeah. Well done."

I retracted my fist, dusting off my hand as I offered genuine praise. It wasn't an empty platitude meant to encourage her, but admiration straight from the heart. To succeed in accelerating her reaction speed in just a few hours... Even taking into account that she possessed the relevant esper ability and an artificially enhanced physique, her progress was absurdly fast. Throughout the session, the thought Is this what a Hero is truly capable of? had been threatening to spill past my lips every few minutes.

Today marked the ninth day since I began instructing her. In truth, today was practically our first day of real combat training and sparring. The preceding eight days had barely been enough to listen to bedridden Astrea describe the conflicting powers tearing through her, and then teach her how to rein them in. Though honestly, suppressing most of those clashing abilities within eight days was already borderline insane. I had projected it would take at least a month, yet she wrapped it up in barely over a week. What kind of overpowered protagonist was she? Because of that, I had scrambled to push up the training schedule, culminating in the girl currently staring back at me with a subtle, conflicted expression.

"...Do you have a question?"

"...No. Thank you, Master."

"Master"—or rather, Sabu.

That was the title she had bestowed upon me from the very first day of training. I had explicitly told her that "Teacher" or "Master" in plain speech was fine, but she insisted on Sabu. Where on Earth had she even picked up that martial arts term?

"That's enough for today's lesson. Dinner time's coming up soon, so let's eat and take a break."

"Yes."

"Oh, right. Is there anything specific you want to read? You seem to spend every evening buried in books lately—"

If there was anything that had grown more comfortable since taking Astrea under my wing, the first was having someone to converse with openly. Being able to speak casually without tiptoeing around awkward polite honorifics was an incredible relief. The second was that the long, empty evenings I used to waste away had transformed into something remarkably productive. Sitting down for proper reading sessions, trading questions and answers with Astrea, or sharing stories—from Earth's past history to the current political state of the Humanity Coalition—was a deeply refreshing experience. Exchanging thoughts on countless subjects, building knowledge, and arriving at conclusions together was nothing short of delightful.

Of course, I could converse and debate with people on the Demon Lord Gallery anytime, but I had never shared my thoughts or struggles regarding Earth there—nor did I have any desire to. There was hardly anyone in that community who could genuinely empathize with my story. Opening up at that tavern in Pandemonium had only been possible thanks to the alcohol and the mood of the moment.

"...Nothing specific right now, but I'll let you know if I find something I want to read."

"All right."

The rest of the evening passed without incident. The two of us cleanly demolished a ten-portion dinner, dealt with the clothes torn up during training, and tidied up the courtyard and hideout. Once the chores were out of the way, Astrea retired to her room and began reading.

The bed where she had lain unconscious had naturally become her nest, and the room she occupied had turned into her private quarters. Technically, she had usurped my old bedroom, but it hardly mattered. The manor-sized mansion I had claimed as my hideout was massive—vast, even. Spare rooms were in surplus, and any one of them would serve just as well as my bedroom. If I felt too lazy to bother, I didn't even need to sleep; I could simply idle away the night in the corridor.

"What should I teach her tomorrow?"

That was the first thought that struck me the moment I lay down in the room two doors down from Astrea's.

What do I teach her next?

I never dreamed I would be agonizing over this so soon. The student surpassing the master was supposed to be a virtue, but there had to be a limit. Watching her demolish my entire planned curriculum and inhale every lesson like a sponge left me thoroughly dumbfounded. Life really was unfair.

Honestly, as I taught her, I felt faint twinges of an inferiority complex—maybe even a sliver of jealousy. I thought I had discarded those petty emotions twenty years ago, but clearly I was wrong.

'If only someone with this talent had been born just a little earlier...'

'If only I had even a quarter of Astrea's natural gift...'

Such stray, idle thoughts had flitted through my mind.

Maybe I should ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠just pass my entire burden onto her...

Part of me genuinely felt tempted to dump all of my knowledge, information, combat experience, ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠and methods onto her, and let her take over my role completely.

"Ha..."

A dry laugh escaped me.

"Get a grip. Stop talking nonsense."

Talk about absurd thoughts. Not only feeling inadequate before a girl practically young enough to be my daughter, but contemplating foisting my own karma and burden onto her shoulders? Browsing the gallery would be a hundred times more productive than rotting my brain with such ridiculous delusions.

"Speaking of which, might as well check the board."

Straining my head was only going to lead down weird rabbit holes anyway, so chilling out with some forum lurking felt like the right call. I manipulated the interface with a few swift gestures to bring up the gallery window. Since it had been two days since my last visit, I had to sift through a mountain of notifications one by one.

It was right as I was methodically clearing through several dozen alerts that something caught my eye.

"Huh?"

What arrested my attention was a series of private messages and the handle of the sender. The sender was none other than Equilibrium. Of course, seeing his handle alone wasn't what shocked me. What stunned me was the sheer volume of messages.

Out of the forty-two unread messages sitting in my inbox, a staggering thirty were from Equilibrium—which is to say, Leon. That could only mean something had happened. As much of a Hero collaborator, shitpost agitator, attention whore, and lunatic as Leon was, I didn't take him for the type to spam my private inbox just to troll me. Opening the messages in a hurry, I read through the contents:

"....Ah."

There had, in fact, been such an incident.

The moment I remembered the conversation I had shared with a dead-drunk Leon right before parting ways at the Pandemonium summit, an icy chill crept down my spine.

"......"

No matter how I looked at it...

"...Am I total scum?"