SLAP, SLAP!
What violently hauled my consciousness up from the abyss to the surface was a sharp pain.
"Ugh!"
The moment I opened my eyes, what I saw was a deeply unfamiliar scene.
My childhood self, that is, not me but the body-swapped Aizel Renhardt, had his open right hand drawn all the way back.
That posture was a full swing.
A chill ran down my spine and my mind snapped awake.
A sharp sense of danger.
The right hand drawn back was about to come flying in with the recoil.
"You want to die?"
The instant I roared.
His posture flinched and stuttered.
WHOOSH!
The fierce wind his palm made sent my hair flying.
THUD!
At the same time, Aizel, having struck empty air, lost his balance and spun right around onto his back.
And then.
"Kgggh!"
The violent pain I hadn't felt through my dazed mind and the threat of the slap came surging up.
The kind right before blacking out.
The seizure of Ether Hyperventilation Syndrome.
What came into my blurred vision was my, no, Aizel's study.
I shouted at Aizel.
"I definitely saw that. We'll settle it later, got it?"
"N-no, I was just trying to bring you around......."
-Master, I saw it. That bastard saw his chance and slapped the hell out of you!
The skull-head shouted in a voice that sounded oddly delighted.
That tattletale bastard.
But it wasn't the time for an argument.
"Open the bottom-right compartment of that wall cabinet."
At my words, Aizel bolted for the wall.
"F-find a sword!"
"W-which one?"
"Shaped like a longsword....... Kk! Short blade, red hilt. Kgggggh!"
The screams wouldn't stop coming out of my mouth.
CRASH!
A racket rang out, and then Aizel abruptly thrust something at me.
A blunt longsword with a red hilt.
The one I'd described.
I snatched it up and shoved mana into it at once.
HMM, HMM!
With an unfamiliar noise, the blade turned red.
"Huh? W-what is this......."
Aizel asked in surprise. But I was in no state to answer.
The mana that had been clawing at the Mana Circuit poured out in gushes down my right hand.
HMMMMMM!
Each time, the blade cried out fiercely.
About three hours passed like that.
"Khh, khh!"
The pain vanished completely, and the mana settled quietly in my Dantian.
With my ragged breath and the pain subsiding, I finally had room to think.
First I groped through the memories of Kalian's body.
The symptom had appeared in Kalian's body around the age of nine.
From then on he'd suffered these seizures once or twice a month at the fewest, five or six at the most.
That timid, passive nature had come from the repeated pain he'd endured since childhood.
My brief musing was cut off by Aizel's question.
"What is this thing?"
What Aizel pointed at was, naturally, the short longsword I'd been holding until moments ago.
Calling it a longsword when it's short does seem a bit contradictory.
"It's a magic item I gave to Brother Stellan when I was twelve."
"Huh?"
"A magic sword that produces Sword Aura the moment you inject Internal Energy."
Along with magical talent, I had an aptitude for taking apart and making magic items.
From a young age I'd tinkered with such things, designing and building them myself.
"Hah! You can make magic items too?"
Aizel asked with an astonished face.
Strictly speaking, it isn't a magic sword.
It was modeled on the principle of the Mana Circuit and made to run on mana alone, so calling it a Mana Circuit Sword is more accurate.
"It's a failure."
"Right, no Sword Aura came out."
"A failure that sucks up every drop of Internal Energy and produces nothing. Back then Brother Stellan slept for a solid week from mana exhaustion because of it....... Huh?"
"What?"
"No, hold on."
Come to think of it, it was strange.
As children, Brother Stellan and I were on very good terms.
Close enough that I made something like that for him.
Back then Brother Stellan lay sick for a week.
For that entire week I never left his bedside.
That's how close we were as brothers.
So how had we grown so distant?
Right, things went bad after Brother Stellan became Patriarch.......
No. Brother Stellan turned hostile toward me, and he did it one-sidedly.
At the time I'd thought it was because he felt threatened that I might shake his position as Patriarch.
But thinking about it now, it was very strange.
In my whole life I had never once shown interest in the Patriarch's seat. My brother knew that.
And then suddenly?
And not simple wariness either, but hatred deep enough to treat me as an enemy?
It made no sense after all.
But what if it wasn't because of the Patriarch's position?
There is one truth I didn't know then and do know now.
At the time the House was wiped out, Brother Stellan was not the real one.
There was a strong chance that the real and the fake had been switched at that point.
After my brother became Patriarch, I entered the Eastern Tower and hardly ever visited the House.
What if, while I was away from the House, the real brother died and a fake went around playing him?
I would have been the person to watch most closely.
At the time I was a promising mage at the Eastern Tower.
Meaning I possessed a mage's sharp intuition, or insight.
If so, I was the one most likely to notice the switch first, so perhaps he'd thoroughly kept his distance so I wouldn't find out?
The pieces fit exactly.
There was no clear physical evidence, but circumstantially it was the most reasonable conclusion.
Until my brother became Patriarch, I had always attended the House's events.
And back then my brother was still the affectionate Stellan.
So, after he became Patriarch.
The point when I was devoting myself to research at the Tower.
That was around when I was twenty-five.
"Phew!"
I'm fifteen now, so that's ten years until then.
Ten years is enough time to prepare for it.
For now, one important thread had come together.
That aside.......
Aizel asked again.
"You made something like this at twelve? You really are as much a genius as Sister Chloe."
Ah, suddenly my whole body ached.
My body had reacted reflexively at hearing that witch's name.
Oblivious, Aizel chattered on.
"My sister made me the Mana Drain Bracelet two years ago."
Chloe is four years older than us. Which means Chloe Facial modified the Ether Suppression Cuffs into the Mana Drain Bracelet at seventeen.
I'm still the better one.
Chloe altered something that already existed; I invented something that didn't.
A failure, of course.
In any case, nothing more could be done today.
The sudden seizure had left no strength in my body.
"Let's go and rest for now."
"Ah, right. It's already dinnertime."
"How have you been handling meals and daily life until now?"
"Uh....... I said I wasn't feeling well and had meals brought to my room, and I spent most of my time here."
Exactly the response a timid guy would come up with.
"Let's go to the room for now. I'll use the attendant's quarters attached to my room, no, your room. We'll eat in your room, and have them bring mine along too."
I never kept an attendant right up until the House was wiped out, so that room is empty.
"Uh, got it."
That night was the first satisfying evening in a long while.
The cooking from the kitchens of the Renhardt main castle, tasted for the first time in nearly forty years, was fine enough to melt the tongue.
The Wheatfield Pig's stir-fried pork is a fine dish too, but a noble mansion's formal dinner is another matter.
The bed in the attendant's quarters was excellent as well, so for the first time since the regression I was able to sleep sweetly and deeply.
***
"This is that, isn't it, Teacher?"
Chloe Facial's eyes turned sharp.
What had come into Chloe's view was a corpse reduced to nothing but bone.
But not the sort you commonly see.
The bones remained in the exact shape of a person, and those bones were pitch black.
Jane, Chloe's teacher, standing beside her, nodded with a grave face.
"Yes, this is a trace of Dark Magic. And what's more......."
Chloe picked up Jane's words.
"Rebound. The recoil from a failed Dark Magic casting."
Get the casting even slightly wrong, and the recoil offers up your own life as the sacrifice.
That is Dark Magic.
It isn't merely that it uses living sacrifices; Dark Magic is taboo because it is that dangerous.
Just then a powerfully built man approached Chloe.
"Lady Chloe, we found three bodies over there, killed in combat."
It was Hans Bantein, Chloe's escort captain.
Chloe's expression hardened once again.
It was the face of someone worried that her brother Kalian might have come to harm.
Reading that thought, Hans hurried on with his explanation.
"None of them is Master Kalian. Two of them appear to have killed each other, and the last one......."
"The last one?"
"Appears to have died at Master Kalian's hand. The traces left on the body are Facial-style swordsmanship."
"Whew!"
Chloe let out a sigh of relief.
But only for a moment.
"Kai, what on earth are you doing?"
Anxiety rose on her face.
First he was off playing hero and wiping out bandits, and now he'd had some out-of-nowhere fight in a remote place like this.
Still, one small mercy amid the misfortune.
"For now the danger involving the dark mage seems to be gone, so we can rest easy on that count."
At Jane's words, Chloe nodded as well.
It was what she'd worried about most while chasing her brother's trail.
The exact circumstances were unknown, but the dark mage had died from a Dark Magic Rebound, so that was one weight off her mind.
Just then a young man came running toward them.
"Lady Chloe!"
He was one of the knights of Chloe's escort guard.
Meeting Chloe's eyes, the young knight spoke quickly.
"We've found Master Kalian's trail."
"Really? Where?"
"That is......."
"Speak quickly!"
Chloe was normally cheerful, but worry for her brother had her reacting with considerable edge.
"He boarded a train."
"A train? To where?"
"Ballonz County."
Chloe's and Jane's faces twisted at the same moment.
"Haa, honestly."
It was because none of it made sense.
Jane spoke calmly to the sighing Chloe.
"One thing is certain, at least."
Chloe knew well what that was.
"Yes. He's consistently heading east. But that makes it stranger. If he keeps going east, then next is......."
"Renhardt territory."
House Renhardt, one of the Empire's Three Great Houses, like Facial.
The Houses were not hostile to one another.
If anything, a loose alliance.
But not so close as to come and go freely without reserve.
"He isn't actually going to Renhardt territory, is he?"
"Let's move for now."
"Haa, yes!"
Chloe nodded, her expression endlessly heavy.
'Just wait until I catch you.'
He was a brother she cherished far too much, but this time she must not let it pass.
***
Ether Hyperventilation Syndrome.
A rare symptom, no, a rare constitution, said to appear in about one in a million.
Ether.
The formless energy drifting through the world along with the air is called Ether.
Living beings absorb this Ether through breathing.
The Ether that enters the body this way is used to sustain the creature's life force, and whatever is left over is expelled through the exhale.
This is the ordinary Ether-breathing mechanism of living beings.
Mages and martial artists twist that process.
They convert Ether into magic power or Internal Energy and store it in the body.
And they sustain their life force through the circulation of magic power or Internal Energy.
Whether magic power or mana, there are various cultivation arts.
Depending on the depth of the cultivation art, the amount of mana or magic power held in the Dantian or the Mana Ring differs.
So what happens if you have Ether Hyperventilation Syndrome?
The body sucks in Ether indiscriminately. The amount is beyond what the body can handle.
The human body tries somehow to expel it and cope.
And when the limit comes?
-A seizure happens.
'Damn it!'
The third day since I'd entered the Renhardt mansion.
For three days I'd been agonizing over this damned Ether Hyperventilation Syndrome.
'I feel like there should be a solution, though?'
-Come on, where would a solution be? The cases are so rare there's barely any research on it.
'This bastard? It's like you're praying for me to die?'
-N-no, that's not it. If something happens to you, Master, what becomes of me?
'Which is why we have to find a method.'
-No, I'm telling you there's no solution, you know? Unless you had two Dantians or two Mana Rings, how would you ever handle it?
'Huh? What?'
-Yes?
'What did you just say?'
-Unless you had two Mana Rings.......
"That's it!"
I shouted without realizing it.