Three Months After the Disciple Left
Three months had passed since Sera left, and today, as on every other day, I was hunting to make ends meet.
"Back again, are you?"
"Yes. Top-grade, as usual."
"You're something else, old-timer."
I'm not an old-timer…
Whether it was the aftereffect of losing my Aura Heart or something else entirely, my ash-gray hair had vanished without a trace, replaced by a white so frail and lifeless it made me look like a withered old man. Cloaked from head to toe, hood drawn and face wrapped in cloth, I could hardly blame anyone for the mistake. There was a reason I went to such lengths to hide who I was.
Mercenary work was a profession steeped in sin. I had never swaggered about drunk on my own power, never abused it for petty cruelty. But a mercenary took contracts, and fulfilling those contracts often meant blood on your hands—blood spilled in the fights and quarrels that came with the job. Blood called to blood. Even if I had never intended harm, there was no telling when the blood I had shed might come looking to claim mine in return.
More than anything, the real problem was that I no longer possessed the strength I had carried as the A-class mercenary known as Steel Jade. The name alone had once been enough to keep most people from even thinking of picking a fight. That protection was gone now.
The Elf's Breathing Method has helped, but "helped" is all it has done.
Three months since my disciple left.
In that time I had learned something clearly enough: the Elf's Breathing Method could only optimize the body. That was its limit. For a warrior who still possessed an Aura Heart, it might have been a priceless treasure—something capable of elevating their abilities by several stages. For me, without one, there was only so far it could go.
"Cough! Cough! Hah. At least the coughing's all it is now. No more blood. Small mercies."
When every coin counted, few expenses stung worse than ruining a set of clothes. That I no longer had to worry about it was a genuine relief—and proof, in its way, that I was getting healthier. So I would manage well enough until my disciple returned.
"So come back safe, kid."
Today, as always, there was nothing a worthless master could do but pray for his disciple's well-being.
Great Mage William Laswell.
"Damn it all!!!"
He was one breath away from death, and that was no exaggeration. The energy he was holding back with his bare body was vast enough to erase the Imperial Capital—the very heart of the Empire—from the map without a second thought.
"I have to hold on! I cannot die here!"
The Emperor was a man who found no easy peace of mind. And a man who could not rest easy was a man who would stop at nothing to secure it. It had not been enough to place every Hero candidate under the tutelage of superhumans and masters; he had wanted a weapon built specifically to kill the Demon King. Even the Empire, however, had only so much information on a Demon King who had last appeared in the distant past. In the end, "a weapon for the Demon King" had simply come to mean a weapon of unprecedented, monstrous scale.
But something like that could not be built overnight. If it had never been made before, there was surely a reason. Greed and recklessness had finally exacted their price. The colossal energy gathered to forge that weapon had run wild, and now it stood on the brink of annihilating the capital itself.
The only elixir capable of curing his only daughter's incurable disease had, of all people, been in the Emperor's possession. William had joined the project late and under duress simply to get his hands on it—and had been swept into this catastrophe the moment he arrived. He could not have felt more wronged. But he could not simply stand by and watch the capital vanish, either. His daughter was here. For her sake alone, he had to stop this—even if it cost him his life.
The problem was that if he died here, even if the Emperor kept his word and handed over the elixir, the cure itself would be impossible to make. Only William could prepare it. And there was every chance that, with no living party left to hold him to the bargain, the Emperor would simply refuse to surrender the elixir at all.
He could not die.
He could not die—and yet—
KRUUUUMBLE!!!!
"I've reached my limit!!!!!!"
In the end, there was nothing left but to release his limiters, seize the explosive surge of mana that flooded through him in that single instant, and force this vast energy skyward—sacrificing his life to do it. Nothing else.
"I'm sorry, Ely."
He had promised to buy her something delicious and come home…
A promise he would not be able to keep.
"If you're going to apologize, you should probably do it to her face."
"Wh— Who's there?"
"Is this really the time for that?"
He had no idea how long she had been standing there, but a silver-haired girl in a white cloak was right behind him.
"K-Kid! A place this dangerous—!"
"Sera."
"What?"
"There's only one person in this world who is allowed to call me 'kid.' I'd prefer you didn't."
She said it with a blank face and an almost leisurely calm. In that same moment, William registered just how absurd the situation truly was. Before him, a torrent of energy was thrashing wildly. He was holding it down as best he could, but its influence was so overwhelming that an ordinary person who drew too close would faint—or die—without anyone finding it strange. And yet this girl stood there as if it were nothing at all.
Which meant…
This girl is that powerful?!
He had seen every kind of superhuman, and not one of them had reached a level like this at so young an age. In that moment, William simply could not fully accept the existence of the girl called Sera.
But whether he accepted it or not, the reality that she was standing here did not change by so much as a hair—nor did the unhurried way she drew her sword.
"Great Mage William. I will save you, and as a result, your daughter will live this time as well. In exchange, I require a Mana Oath."
"……."
A Mana Oath.
Exactly what it sounded like: a vow sworn upon one's mana. It was the oath a mage made when they meant to keep a promise absolutely—or when they pledged total loyalty, staking everything they were, to a lord of their own choosing.
It was said to have been created by an ancient emperor who had feared the monstrous power of the Great Mages of that age. Most people knew it only as one of the forgotten techniques of antiquity. Only one living person still truly understood it: Great Mage William himself. And he had never told a soul—not his closest friends, not even his daughter, to whom he would have gladly explained anything she wished to know. Yet this girl possessed information no one should have possessed.
"Hah. I suppose there's nothing more foolish than treating the strange as strange."
The mere fact that a girl like this could stand here so calmly was already beyond reason. Anything stranger than that would hardly be surprising. Which meant this thoroughly unnatural girl was fully capable of doing things that, by his standards, defied all sense. That was the single most important premise he had right now. So he would place his bet on her. That was William's decision.
"If it gets me out of this, anything."
"I'd take the oath this very second if I could. But that seems impractical."
William could not help thinking that, for a child, this girl suffered from a terminal case of suspicion.
That idle thought lasted only until the next moment—when what unfolded before his eyes forced him to doubt them entirely.
The vast energy is avoiding her on its own? No—the aura coming off her is blocking it from getting near?
Aura gathered along the girl's blade. This was not merely the handling of aura. This was the complete mastery of it, the state of sealing it wholly into a weapon—the Aura Blade. To say that no one of her age should ever be able to reach that transcendent realm would not have been an overstatement. And yet she had already arrived there. That alone was shocking enough. But the most shocking thing of all was—
What… what in the world is that?
What radiated from that Aura Blade was the unknown itself. Even standing at the transcendent height of a Great Mage, he could not understand—not in the slightest, not at all—the phenomenon her Aura Blade was producing.
But whatever he thought of it, the fact remained: her Aura Blade was annihilating the vast energy.
Annihilating it, literally. This was not the ordinary logic of water extinguishing fire. It was as if the water itself were vanishing—as if the water were being erased from existence. It was an aberration impossible under the laws of nature and the laws of magic alike. To the faithful, it would have been a miracle without reservation.
In that moment, William arrived at a single conclusion.
"The Hero…"
"I have no particular desire to become the Hero. But I have more than enough desire to erase the Demon King."
The light of her Aura Blade swelled, and the vast energy began to vanish as though darkness had touched a pure light.
"If the one who defeats the Demon King is the Hero, then I'll gladly be the Hero."
With those final words, her Aura Blade began to dance.
What should have been recorded as a great tragedy of the Empire—an event that had most certainly occurred—was made as if it had never happened at all.