The Disciple Picked Up a Fortuitous Encounter
I told the kid it was a family secret for now. I lied and said that if anyone found out she had two Aura Hearts, mages would come to dissect her, so she must never let it slip. Honestly, I didn't think the odds of mages discovering it were high. Perfectly controlling someone else's Aura Heart wasn't an easy feat.
If someone had experience as an Aura Master before, maybe. But that was the kind of thing that only happened in absurd fantasies.
This little disciple of mine would only ever use my Aura Heart when her life was hanging by a thread. It was literally a spare life I'd planted in her, born from the simple wish that she wouldn't die.
And wasn't that enough?
Being able to help my disciple when she was in mortal danger.
As a master, that was more than satisfying…
"Cough! Cough! Damn, this still hurts like hell."
There was a reason they called it an Aura Heart. It was the very life of a warrior, and the more it was tempered, the more it became the core of the body. So when that core suddenly vanished, the balance collapsed. The resulting rupture began tearing the body apart for real. In the worst case, it could kill you.
"Haa. Like I'd die that easily."
During my mercenary days I'd faced death more times than I could count, and I'd always come back with all my limbs intact. So this time, too, I would adapt somehow and survive. That meant the kid would never have to feel guilty over me later. I was confident I could live just fine without an Aura Heart.
"Cough! Cough!"
So everything was fine.
Sera couldn't believe it.
Accepting someone else's Aura Heart wasn't the end of it. It was someone else's to begin with. Taming it and making it completely her own should have been anything but easy, even for someone with her experience as an Aura Master. It was the kind of ordeal that demanded long, grueling effort just to make possible.
That was normal.
That was how it was supposed to be.
And yet—
It's warm and soft… almost like it's protecting me…
Taming? Unnecessary. Jade's Aura Heart offered her not the slightest resistance, so there was no need. It followed her will as obediently as a well-trained dog. And even while doing so, it was careful not to strain her young body. This was a miracle beyond anything even she—with all her accumulated experience and knowledge—could have predicted.
Or maybe the Aura Heart was simply as hopelessly kind as its original owner.
You idiot…
She had finally obtained the thing she had longed for so desperately, and the compatibility was so perfect that taming wasn't even required. Yet Sera couldn't feel happy at all.
Because she had reached for it so desperately for so long, she knew exactly what it meant to give an Aura Heart to another person—and how much pain came with it. You didn't die immediately, but the price was so horrific that dying wouldn't have been strange. That was why Sera herself had given up. She had never imagined that after resigning herself again and again, after so much time had passed, it would suddenly fall into her hands like this.
So even though the miracle had become reality, she couldn't simply rejoice.
"Cough! Damn it. Got it on my clothes. Gotta change before the kid notices."
Sera had reached the realm of superhumans many times. That meant that even in her current child's body, she could freely control her senses. So every quiet mutter Jade made reached her ears perfectly. And every time he hid away to cough up blood, Sera always knew.
She couldn't leave things like this.
I'll need to prepare something.
My body kept getting worse. Reality wasn't kind enough to be overcome by willpower alone. In the end I had to lie to the kid that it was a cold and become a proper invalid. Me, a high-level expert, catching a cold… Under normal circumstances no one would have bought that lie, but luckily she was a kid who didn't know how the world worked, so it worked.
But would this little one train properly on her own?
That was when she spoke.
"Master."
Come to think of it, when had this kid started calling me "Master" so earnestly? It had started not long after the Aura Heart transplant, I was pretty sure.
"Hmm? Cough. What is it?"
"I found something strange."
"Something strange?"
What the kid brought was a book that looked quite old. As an A-class veteran mercenary, I had plenty of experience. Handling the loot from bandits I'd been hired to wipe out was basic of basics. So I could appraise it at a glance.
Pretty old. Hmm.
"Where did you find it?"
"I was out gathering medicinal herbs and felt like something was there, so I dug and this came out."
"Why herbs?"
"I thought they might help a little with Master's cold."
"……"
An Aura Heart transplant wasn't something herbs could fix. But just knowing she felt that way was enough to make something inside me feel healed. Ah. So that was why everyone worked so hard to take on apprentices or disciples? If I'd known I could feel something like this, I would have taken a disciple ages ago…
"So what's it about?"
"This? Let's see."
"It's about a special breathing method of the elves. Hoo."
Watching Jade lose himself in the book with genuine fascination, Sera felt her efforts had been worthwhile. Of course the book was her own creation. For someone who had accumulated so much experience and knowledge through countless regressions, fabricating a convincing work like this was as simple as drinking cold soup—as long as she had enough aura. And thanks to the Aura Heart Jade had given her, she had more than enough. Creating a perfect piece was no difficult task for her.
The content was exactly what Jade had said: the Elf's Breathing Method.
One of Sera's many experiences had been among the elves. In exchange for helping an elf who had been captured as a slave, she had lived for a time in the hidden elven village inside the World Tree's barrier, learning their culture and their unique techniques. The elves' breathing method had been one of them.
Even elves were sometimes born with disabilities or frail bodies from childhood. Yet every one of them grew into peak physical condition and lived their lives fully. What made that possible was the Elf's Breathing Method—a special technique that guided even a weak body toward strength. It was an extremely rare breathing method that allowed one to absorb the natural mana present everywhere into the body.
She had prepared it for the person who would weaken after giving her an Aura Heart. She had never expected that such a person would actually appear and that she would one day hand this over.
She was glad.
"Hmm. This will be useful for you too."
"……"
No, why are you thinking about how it might help me before even considering using it yourself?
How on earth had someone this hopelessly kind managed to live as a mercenary long enough to earn the moniker Steel Jade? Sera couldn't understand it at all.
They say a master learns while teaching a disciple.
Jade could feel that truth clearly now.
If Sera hadn't been beside him, mastering the Elf's Breathing Method alone would have taken considerable struggle. Because she absorbed it so effortlessly right next to him, he was able to learn it far faster than expected. He had already known she was beyond the ordinary, but Sera seemed to be a genius who far surpassed even his wildest estimates.
Leaving a kid like this with me… Looks like the imperial officials weren't doing their jobs properly.
With talent of this caliber, she should have been entrusted to someone in the realm of superhumans, not a high-level expert like him. The child herself wouldn't have hidden her aptitude, so the officials must have botched the evaluation. Well, thanks to that he got to teach a child who learned ten things for every one he showed her, so he wasn't complaining.
"Master, your breathing is off."
"Ahem. My mistake."
Now she was even teaching him.
His pride wasn't wounded. The fact that this child was a genius simply meant her mortality rate was lower. He considered that a good thing. Wasn't it only natural for a master to be glad that his disciple's chances of dying had decreased? Even if her talent was so overwhelming that it made his own look insignificant, feeling jealousy or envy over it would disqualify him as a master—and as an adult.
The only problem was—
I'll run out of things to teach her soon.
But that, too, was a good thing.
The faster this child absorbed everything he had, the faster her survival rate rose. There was nothing bad about it.
It only meant the time of parting would arrive a little sooner. That was all.
Sera was an expert on disciples. The phrasing was a little strange, but nothing described her more accurately. She had taken countless masters. Of course, none of them in the present knew she had once been their disciple. She had studied under every kind of superhuman. Sword Masters were the baseline; she had even taken a Grand Sage as her master. Under a Sword Master she had been called a future Sword Saint, had risen to the rank of Sword Marquis, and had even defeated a Sword Saint to claim the title herself—her master being the very Sword Saint she had defeated. She had become a Grand Mage as a Grand Sage's disciple. And she had walked entirely different paths under entirely different masters as well.
Her masters had walked the path of light, and some had walked the path of darkness. That was why she was, quite literally, the greatest expert on disciples who had ever lived—having experienced so many of them.
And to someone like her, Master Jade was—
hopelessly, irredeemably soft on his disciple. Of course he was the kind of man who would transplant the crystallized essence of a lifetime of martial achievement—his Aura Heart—into his disciple. She had never once seen a master who sincerely rejoiced at his disciple's growth.
And wasn't that only natural? When someone came sprinting up the path you had walked with such difficulty, treating it like nothing and closing in on your heels… even if they were your disciple, feeling a twinge of resentment was only human.
She had assumed Jade would feel the same, so she had been holding back to some degree. But Jade was the opposite. He seemed to prefer watching her absorb everything he had and grow at a terrifying pace. And Sera could easily read the reason: because doing so raised his disciple's survival rate.
He really was a hopeless disciple-doting fool. This man who was her master.
I completely mastered the Elf's Breathing Method. My life improved dramatically because of it. I was even well enough now to serve as a sparring partner for Sera.
Tak! Tak! Tak!
"Yes! Just like that!"
"Yes, Master!"
Honestly, it was starting to feel less like I was sparring with Sera and more like she was adjusting her training to accommodate me. Even though I wasn't really teaching her anything proper, Sera kept growing. She grew on her own without being taught. How terrifying was that kind of talent? If someone treated martial arts as their entire life rather than a means the way I did, that monstrous gift might have driven them to curse even their own disciple out of sheer envy—and it wouldn't have been strange.
From my perspective, she was simply a welcome presence who raised my disciple's survival rate.
And that also meant—
that the parting with my disciple was drawing closer, faster.
And for me, that was—
never,
truly never,
a welcome thing.