Chapter 4

Chapter 4. The Optimal Answer

***

"AIRI?"

It was an alien name.

Before the regression, I had torn apart and rebuilt the fifth-generation system code countless times, but no Add-on like this had existed anywhere in it.

I had never seen it even in the lists of illegal programs traded deep inside the Association server or on the black market.

If so, there was only one answer.

"Are you a byproduct of [Inheritance]?"

[Correct, Inheritor.]

A dry affirmation.

Holding my still-aching arm, I stared at the chatbot icon floating in the air.

What my brother had left behind was not merely power. It seemed he had even attached a secretary to manage his data.

"Functions?"

[Performs Inheritor skill synchronization, data backup, combat analysis, and tactical support.]

"Good. Analyze the battle just now."

An order without hesitation.

As a performance test, I needed to confirm the disastrous report card of what happened when a mage picked up a sword in objective numbers.

As if it had been waiting, AIRI displayed a red hologram graph in the air.

[Combat Efficiency: 12%.]

[Detailed Analysis: Aura absent. Physical level insufficient.]

[Overall output Overclock state.]

[Conclusion: Peak inefficiency. Shortcut to self-destruction.]

"······Accurate."

A bombardment of undeniable facts.

I pressed the cold canned coffee against my forehead.

As the heat faded, my overloaded head began to turn coldly.

To use an analogy, it was like forcibly cramming an F1 racing car engine into a gasoline compact car.

The body screamed because it could not endure the engine’s vibration, and since diesel was even being poured in as fuel, it was only natural for the engine to explode the moment it started.

"Mages use mana. Swordsmen use Aura."

Common sense.

Different fuels, different circuits.

The two were realms that could not mix, like water and oil.

If a mage tried to use Aura, his blood vessels would burst and he would die. If a swordsman forcibly operated mana, his brain would burn.

That was the law of this world.

[A mage Class cannot draw out 100% efficiency from the Sword Saint’s skills.]

A row of zeroes continued endlessly below the decimal point.

That was my current position.

"So, you’re telling me to give up mana and pick up the sword?"

AIRI did not answer.

Silence meant affirmation.

My fingertips trembled faintly.

The magic knowledge of the 9th Circle. And the absurdly overpowered Trait, "Tree of Sephiroth."

Throw that away and learn the sword again from the beginning?

That was insanity.

No, for me, it was impossible.

To personally tear down the pinnacle of magic I had built over ten years.

The Evil God Dragon was a monster that had chewed up both the Archmage’s forbidden spells and the Sword Saint’s slashes.

With only one of the two, I could never pierce even that bastard’s scales.

That had already been proven in the future.

The answer was set. I had to have both.

No, I had to combine the two.

Even if I had to mix water and oil, I had to create a new fuel.

"What is the optimal answer in the current situation?"

For a moment, noise flickered across the screen.

AIRI’s voice sank even lower. It seemed to be the conclusion reached after mechanical calculation.

[Reasonable proposal: transfer [Inheritance] to another Awakened with high Aura Aptitude.]

"Don’t give me that bullshit."

A hollow laugh burst out.

It was a machine-like suggestion, so rational it was disgusting.

I firmly shook my head.

"That is never going to happen."

[I cannot understand. Inheritor, you are specialized in magic. Considering efficiency···.]

"Efficiency?"

I clenched my fist until it felt like it would break.

This was not simple skill data.

It was my brother’s life.

It was the legacy he had left after erasing even his own existence to save me.

Hand that over to someone else? For efficiency?

"Even if my body breaks, I’ll carry it myself. That’s the price."

[······Inheritor’s will confirmed.]

[Alternative suggested. Entry into the 'Altar of the Inheritor' is recommended.]

"You should’ve led with that."

***

When I opened my eyes, a cool chill wrapped around my ankles.

This was not the café in reality.

Instead of the coffee scent I had been smelling just moments ago, the metallic tang of blood and the smell of dust stabbed my nose.

A vast circular colosseum.

The stands were empty, and only silence lingered.

The cold sensation of the flagstones laid across the floor traveled through the soles of my feet and up my spine.

For a virtual space, the sense of reality was far too vivid.

Even the texture of the wind brushing against my skin felt alive.

"The Altar of the Inheritor."

In the center stood altars engraved with strange patterns.

When the wind blew, my clothes fluttered, and every breath filled my lungs with cold air.

[This is the deep space of consciousness.]

[One minute in reality equals one hour here.]

[External physical laws do not apply.]

In simple terms, it was a room of time.

So this was the secret behind how Sword Saint Kang Tae-yoon would disappear for days at a time and return a monster.

When others trained for one year, my brother had endured decades alone in this place.

[Warning: death here means mental extinction.]

[In reality, you will enter a brain-dead state.]

[Proceed?]

I clenched my fist tightly.

The pain of my nails digging into my flesh sharpened my senses.

Brain death? After seeing the destruction ten years later, did that matter?

"I die here or I die later..."

I nodded without hesitation.

Blue flames surged around the altar.

A virtual Gate opened, and familiar, horrifying presences poured out.

Skeleton Soldiers.

The same creatures I had faced at Donggureung earlier.

But they were exuding an even more ferocious aura than they had in reality.

"Good. Before that."

I closed my eyes and steadied my breathing.

It was time to attempt an insane act that had existed only in theory.

"Skill activated. [Synchronization]."

HUM—

My heart thrashed irregularly.

The pure mana flowing through my blood vessels was forcibly twisted.

Agony came as if shards of glass were flowing through my veins.

The sensation of my internal organs twisting made me retch.

[Warning! Mana Circuit backflow detected.]

[Aura generated inside body. Unstable!]

AIRI’s warning blared in my ears.

I ignored it.

Skill [Synchronization].

A passive skill that forcibly generated Aura in a mage.

Since it amplified life energy by burning mana, its efficiency was nearly garbage, and one wrong move could lead to mana runaway.

A suicide technique no normal mage would ever take.

Even the guide described it as "strictly forbidden."

But right now, this was all I had.

To use the Sword Saint’s skills, I needed Aura.

I had to run mana and Aura, two hearts, at the same time.

"Kgh···"

Heat poured out from my whole body.

Cold sweat flowed down like rain.

It felt like sprinting at full speed while holding water in a paper cup.

If it spilled, I died.

[Analysis complete. You are barely holding on.]

[Currently outputtable Aura Efficiency: 10%.]

"That’s enough···."

A number that did not even reach the tip of Sword Saint Kang Tae-yoon’s toes.

To think I was burning my blood vessels just to gain this little power.

But it was enough.

"I don’t need support. I’ll do it my way."

Step, step.

Thirty Skeleton Soldiers tightened their encirclement.

Their rusty blades struck one another, making a chilling sound.

Killing intent that cut into the flesh.

Instead, my mind cooled coldly.

Control it, and it becomes an opportunity. Lose it, and death follows.

I adjusted my grip on the wooden sword manifested in the virtual space.

"Come. I’ll grind you to dust."

***

It was hell.

With 10% Aura, even breaking a Skeleton Soldier’s bones in one blow was difficult.

When I cut down one, two more charged in.

When the wooden sword broke, I used my fists. When my fists shattered, I tore with my teeth.

My vision flashed red from mana backflow.

It felt as if my heart would burst, but I could not stop.

If I stopped here, I would have no face to show my brother.

"Haaaaah!"

The final strike.

The Aura I had wrung out exploded at the tip of the wooden sword.

CRACKLE—!

The sword imbued with flame and lightning roared as it crushed the skull of the last Skeleton Soldier.

"Hoo··· whew···."

My legs gave out, and I collapsed.

Bone fragments filled every direction.

[The trial at the altar has ended.]

AIRI’s voice felt distant.

The floor of the altar began crumbling away.

A sensation of falling.

I was sucked into endless darkness.

"Hah...!"

I inhaled sharply and opened my eyes.

My heart was beating like mad.

The bloody taste of iron filled my mouth.

"······."

My surroundings were noisy.

The white noise of the café. Murmuring people. The sound of a coffee machine running.

A peaceful reality far too different from the altar where I had been risking my life in a blade fight until moments ago.

"Ha··· haha···."

I wiped the cold sweat from my forehead.

My hands were trembling faintly. I did not even have enough grip strength left to hold a cup.

I checked the clock on my phone.

"I spent 30 hours rolling around in there."

My real body was fine, but my mental fatigue had exceeded the limit.

I felt Phantom Pain, as if every muscle in my body were screaming.

But a strange sense of elation lingered.

I had succeeded.

The sensation of converting mana into Aura. I had taught my body that razor-thin tightrope act.

Although it had been closer to an ugly brawl, a mage had cloaked himself in Aura and survived close combat.

I rose from my seat.

My legs trembled, but I forced strength into them and endured.

Leaning on the table, I took a deep breath.

I had to return to Donggureung.

There had been no level-up, but my hands remembered.

Before this sensation disappeared, I had to confirm it in actual combat.

But before that, I needed supplies.

The wooden sword that was my brother’s legacy had been shattered inside the altar.

I needed a weapon in reality.

I could no longer hold out with a toy-like wooden sword.

"Hunter’s Depot."

A Hunter equipment specialty store two blocks away from Donggureung.

The neon sign above the old signboard flickered with static.

The exterior was shabby, but everyone in the know knew it was a hidden gem.

A place that mainly handled goods on the border between illegal and legal.

When I opened the door and entered, its distinctive smell stabbed my nose.

The smell of cheap anti-rust oil, leather, and cool metal mingled in the air.

This side felt far more comfortable than the scent of perfume at a department store.

Because it resembled the smell of a battlefield.

"Welcome."

A dry voice came from behind the counter.

A man wearing oil-stained work clothes.

His eyes looked hollow, but the way his hand moved as he wiped a blade with the cloth he held was anything but ordinary.

Small scars on the backs of his hands. Joints thick with calluses.

Beneath his short-sleeved shirt, the edge of a hidden tattoo peeked out.

"From a forge, maybe."

The inside of the shop was cluttered.

Machetes, field shovels, and crude cold weapons modified for Hunters hung across the walls.

An age where Gates had become everyday life.

Now people bought self-defense weapons here the way they bought triangle rice rolls at a convenience store.

I approached the display case.

Longswords, rapiers, greatswords.

Every one of them was a crude mass-produced model.

They looked flashy on the outside, but their durability was pathetic factory quality.

I picked up one sword.

It was heavy. But its center of gravity was a mess.

The weight leaned toward the front.

Swinging something like this would tear the wrist ligament first.

In actual combat, it would only be a metal club that got in the way.

"Hmm."

I picked up another sword. This time, I let a very slight amount of mana flow into it.

The thin Aura film covering my fingertips became an appraiser’s lens.

Tingle.

I felt a weak resistance.

This one’s mana conductivity was trash.

When I sent mana through it, the flow inside the blade kept cutting off.

If I used something like this, the sword would burst apart first after a single skill.

For over ten minutes, I handled the swords in the display case.

Sending mana through them, checking their centers of gravity, putting them down.

Repeating the same task.

"Well, aren’t you picky."

At some point, the shop owner had approached and was watching me while standing at an angle.

The cigarette in his mouth was not lit.

His eyes sharpened.

He had noticed that I was not some lukewarm customer looking for simple self-defense.

"Doesn’t seem like you’re a newbie."

His gaze stopped at my fingertips.

He had probably sensed the faint mana waves I had released.

As expected, he was not a simple merchant.

"Do you have anything light and sturdy? It’d be nice if it conducted magic power too."

"Greedy, aren’t you? You’re looking for that here?"

The middle-aged man snorted, but still rummaged through a box tucked away under the counter.

From a dusty cardboard box, he pulled out an object wrapped round and round in newspaper.

THUD.

He threw it toward me.

"Catch."

I snatched it out of the air.

The moment it touched my hand, I felt it.

A grip that fit perfectly.

When I drew it from the scabbard, a Short Sword with a crude black handle was revealed.

The blade length was about 50 centimeters.

A practical combat blade made only to cut and stab, without a single flashy decoration.

Oil gleamed over the sharply honed edge.

"Oh."

The moment I gripped the handle, a tingling thrill ran through my palm.

When I sent mana through it, it absorbed it like a sponge without resistance.

The alloy ratio was incredible.

It clearly contained a very small amount of Mithril or used a magic-friendly ore.

With this level of conductivity, it could handle my mana and Aura at the same time.

WHOOSH—

I lightly cut through the air.

Perfect balance that placed no strain on the wrist.

A weight even a mage’s poor strength could handle well enough.

And an appropriate length that would not catch even inside narrow dungeons.

I was lucky.

---