A Guide Left Behind

Most people breathe in much the same way, but the breathing of mana is entirely different.

The methods of absorbing mana are as diverse as humanity itself, and the most efficient, structured systemization of these methods is what we call a mana cultivation technique.

In short, a mana cultivation technique is the art of manipulating mana—a collective term for the sequence of drawing ambient mana into the body, storing it, and channeling it back out.

What I was doing now was no different.

I gathered the mana rising from the leyline and drew it into my body, guiding the energy coursing through my veins down to my dantian to form a vessel.

This vessel was the mana core.

The mana core was the foundation of all power. The sheer volume and purity of the mana one could store within this core nestled in the dantian served as the ultimate measure of strength.

Ultimately, the mana core forged through a cultivation technique was nothing less than a second heart to mages and knights alike.

"Phew..."

The mana flooding my body clashed violently around my dantian, asserting its raw, untamed presence.

A wave of sharp pain washed over me, but I focused my mind and reined it in. Slowly, I gathered the residual energy trapped within my body and exhaled it.

The breath I released was thick with the scent of condensed mana.

"Unbelievable."

It was truly worthy of being a secret technique of a prestigious magic family.

The Benheim family's mana cultivation technique was superb. It was so exceptional that even scouring the depths of my past-life memories, I couldn't recall a single method that manipulated mana with greater efficiency.

Yet, what I sought was an ultimate technique that surpassed even the Benheim method—one capable of transcending the absolute hierarchy of the Archduke of Demonic Magic.

Creating a new mana cultivation technique was akin to stepping off a well-paved road to blaze an entirely new trail. Those who achieved such a monumental feat were revered as Grandmasters.

Considering how few individuals in the history of the continent had ever been recorded as Grandmasters, what I was attempting was a task bordering on the impossible.

Just as Lunia had said, even if I possessed talent rivaling an archmage, and even with the countless experiences I had honed in my past life, conceiving an entirely new mana cultivation technique was no simple matter.

And it certainly wasn't something that could be forged overnight.

"It's still not enough."

I picked up a fallen branch nearby and condensed the ambient mana around it. Thanks to the unique properties of the leyline and my past-life ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠experience, it wasn't particularly difficult. A faint, shimmering film formed, wrapping around the wood.

Up to this point, it was aura.

From here on, it was magic. I raised my left hand and formed the rune for Kenaz, immediately engraving it onto the branch.

*Flash!*

As expected, the aura and the magic failed to harmonize, violently scattering into nothingness.

"Tsk."

I clicked my tongue in frustration.

It wasn't that I had made no progress at all.

I had adapted the Benheim cultivation technique to suit my own body, blending it with the hard-won experiences of my past life. Yet, the method of containing both magic and aura within a single vessel remained completely shrouded in mystery.

While aura and magic were identical in that they both drew from mana, their fundamental natures were entirely different.

Forcing two opposing forces of mana into a single vessel was incredibly dangerous. Because they conflicted so violently, any imbalance could cause the mana core to collapse, leaving me permanently crippled.

To harbor two distinct types of mana within one body, I needed to strike an exquisite balance where neither suppressed nor eroded the other.

It was a feat requiring absolute, razor-sharp precision—like balancing a heavy weight on the tip of a needle.

This was precisely why the vast majority of those who styled themselves as magic swordsmen on the continent never rose above being third-rate.

"...In the ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠end, practice is the only way forward."

I had no idea how many days, or even weeks, this would take.

It might even prove entirely impossible.

Even so, I had to perfect this technique and surpass the Archduke of Demonic Magic.

Because that was the promise I had made.

"Whew."

Letting out a long sigh, I sat back down and began to review the cultivation formula once more.

It was then.

"Hey there."

A familiar voice drifted over.

Turning my head, I saw the very culprit behind all my current suffering standing there with a bright, cheerful grin.

It was Lunia. She held a basket in her hands, packed to the brim with food.

"What brings you here?"

"What do you mean 'what ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠brings me here'? I came to see you, of course. I heard you haven't eaten a single thing since you shut yourself in the leyline."

Lunia strode over and thrust the basket toward me.

"Here, take it."

I reflexively caught the basket.

"I personally asked the chef to make this. I told him to pack in as much meat as possible. Sheryl told me, you see—she said you're a terribly picky eater."

"..."

It seemed Lunia's meddlesome nature hadn't changed one bit, whether in this life or the last.

"Aren't you going to thank me?"

"I don't recall asking for this."

"Ugh, you are so boring."

Lunia puffed out her cheeks in a pout. I let out a soft chuckle, pulling a piece of beef jerky from the basket and popping it into my mouth.

Even before my regression, Lunia used to bring me meals just like this.

As I drifted into nostalgia, Lunia spoke up.

"You're practicing the mana cultivation technique right now, aren't you?"

"How did you know?"

"I have my ways. I saw Uncle Allet sneaking into the treasury earlier. But honestly, it's so fascinating. I've never seen an outsider be allowed to learn our family's cultivation technique before."

Lunia's eyes sparkled with curiosity. Her gaze swept over me, seemingly measuring the flow of mana coursing through my body. Suddenly, her amethyst-purple eyes widened.

"Wait... have you already absorbed mana into your body?"

"More or less."

"No way. Already?!"

Lunia looked utterly flabbergasted. And with good reason. Even those with exceptional mana sensitivity usually took several days to successfully absorb and store mana for the first time. Having compressed that entire process into a mere half-day, her shock was entirely justified.

"You're a genius, aren't you?"

"I wonder."

I had already seen a genius who far surpassed me in my past life.

In fact, I was looking at one right now.

Yes. The girl standing right in front of me, her round eyes sparkling with curiosity. An anomaly of an archmage who had ascended to the 8th circle in a human body.

The Golden Archmage who had stood shoulder-to-shoulder with the Archduke of Demonic Magic: Lunia Erahan von Benheim.

Once her talent fully bloomed, she would easily surpass even the family head, Stern, to become an unrivaled archmage.

"So, what do you actually want?"

"Do I need a reason to come see you?"

"Not necessarily, but..."

"Well, actually, there is one thing I wanted to ask."

"What is it?"

"That thing you did the other day... how did you do it?"

Lunia's gaze drifted down to the branch I was still holding.

"When we were attacked at the graveyard... how did you slice through their magic like that? And you used that same trick to beat my brother, didn't you? It's so obvious."

It seemed Lunia was deeply intrigued by my ability to cut through magic.

She had sought me out for the exact same reason in our past life. Lunia was always Lunia.

Chuckling softly, I pointed to my own eyes.

"My eyes are just a bit special. I can see the gaps—or rather, the structural flaws—in magic. I can see exactly where to strike."

Magic, ultimately, was nothing more than a vortex of mana. The constantly shifting vibrations of mana inevitably created minor structural flaws. If one could exploit those weak points, even a tiny disruption could cause the entire spell to collapse.

"How fascinating... I've never heard of anything like that. I think I finally understand why Father brought you into the family."

Lunia leaned in close, marveling at my explanation. She peered intently into my eyes, studying my pupils.

"Hmm... No matter how much I look, they just look like dead fish eyes to me."

"..."

Her blunt, unfiltered way of speaking was exactly as I remembered.

As my expression soured, Lunia suddenly spoke up.

"Want me to help you?"

"With what?"

"With your cultivation. You're trying to form a mana core, right? Believe it or not, I've been praised for having far better mana sensitivity than my brother."

Lunia puffed her chest out proudly. In truth, the Lunia of my past life had been an absolute prodigy in mana manipulation and sensitivity, completely peerless in her craft.

But that was the future. The current Lunia was still nothing more than an unblossomed bud.

"There's no point in getting help from a little kid."

"Who are you calling a kid?! We're barely any different in age!"

I ignored her protests and closed my eyes.

The mana I had drawn in through the Benheim technique still circulated within me, but I had yet to find a way to split this energy into aura and magic, and then store them both within a single core.

Creating an entirely new cultivation technique was not a problem that could be solved by sheer effort alone.

I let out a frustrated sigh. The path ahead was completely blocked. At this rate, I would have to remain holed up in this leyline for a very long time.

When I finished my meditation and opened my eyes, Lunia was still sitting there.

"Seriously, you are so annoying."

Lunia pouted, her lips jutting out in irritation.

As I stared blankly at her pouting face, a sudden spark of realization flashed through my mind.

In truth, it hadn't made much of a difference back then.

Even with Lunia's help, my body had already been too warped. Having cobbled together multiple third-rate techniques, my mana core was like a hopelessly tangled knot.

Yet, Lunia had persisted, constantly channeling her mana into my body. Even though it seemed to have no effect, she kept doing it, day after day, without fail.

Back then, my lack of magical knowledge prevented me from understanding her intentions. I had even foolishly suspected that she just wanted an excuse to look at my bare chest.

But now, having learned the Benheim family's unique cultivation technique and looking at this young Lunia, the truth finally clicked.

The specific flow of mana Lunia had channeled into my body under the guise of "treatment."

It had undoubtedly been the Benheim cultivation technique.

But it was different from the original.

It was a customized version, personally modified by the archmage Lunia, designed solely for me.

A thoughtful guide left for a swordsman attempting to tread the path of magic.

The pathways Lunia had carved into my body remained vividly etched in my memory.

If Lunia had intended all of this, including my regression...

'What a terrifyingly clever woman.'

Grumbling internally, I called out to her.

"...Hey."

Not the Lunia of my memories, but the young girl standing before me.

"What? Finally ready to swallow your pride and ask for my help? Hehe."

"Something like that. Can you do me a favor?"

"Sure! I'll help. What do you need me to do?"

Lunia nodded readily, and I promptly pulled off my shirt. Ignoring her sudden fluster, I spoke calmly.

"Channel your mana into my body. Pour in as much as you can."

I was going to reconstruct the legacy left by the future Lunia using the raw power of the past Lunia.

For some time, Arno von Benheim, the successor of the Benheim family, went about his days feeling as though he were floating in a dream.

Nothing had outwardly changed. He woke up in the morning to study magical theory, and after lunch, he trained alongside the family's mages.

*Thwack!*

As the spear of rune magic summoned by Arno struck the dead center of the target, a burst of applause erupted from the onlookers.

"Incredible, Lord Arno!"

"At this rate, you'll reach the 4th circle in no time! Truly, a heaven-sent talent!"

The mages showering Arno with flattery were all from the branch families.

Lacking the talent to learn the Benheim family's core secrets—and having long given up trying—these sycophants clung to Arno, the future family head, hoping to catch whatever crumbs fell from his table.

Until recently, Arno would have basked in their envious, adoring gazes, his pride swelling.

But lately, it only left a bitter taste in his mouth.

"Tsk."

Arno turned on his heel. The mud splattered on the hem of his trousers irritated him, but what irritated him far more were the memories that constantly plagued his mind.

His duel with the outer-gate mage, Raygan.

In that duel, Arno had been utterly and miserably defeated.

Even now, whenever he recalled that moment, his jaw throbbed where he had been struck.

'I lost. There's no denying it.'

He had no intention of making excuses.

Arno was the direct heir of a prestigious magic family. Raygan, on the other hand, was a lowborn mercenary of unknown origin.

Arno had been raised in an incomparably superior environment.

Yet, the victor was Raygan.

He could try to blame it on carelessness, but nothing could erase the fact that he, a 3rd circle mage, had been defeated by an outer-gate mage who didn't even have a circle.

He tried to throw himself into his training as usual, but he couldn't focus. Every time he tried to channel magic, the phantom sensation of that crushing defeat surged back to life.

"I'm still not strong enough."

The thought drove him to train even harder.

Arno was destined to become the patriarch of the Benheim family. He had to possess the strength worthy of that title.

Around that time, the patriarch, Stern, summoned Arno to his study.

"Arno, is your jaw alright? The bruising is still visible."

"Ah..."

Rather than scolding his son, Stern looked at the fierce determination in Arno's eyes and smiled with satisfaction.

"I hear you've been spending all your waking hours in the training grounds lately."

"Yes, Father."

"Does the defeat sting?"

"Yes. But it was entirely due to my own inadequacy."

"I know."

Arno's shoulders tensed at his father's blunt acknowledgment. But instead of reprimanding him, Stern continued in a gentle tone.

"However, the defeat you suffered is a priceless lesson that cannot be bought. In a real battle where lives are on the line, you are never given a second chance to correct your mistakes. I believe you will use this defeat as nourishment to grow even stronger."

His father's words pierced Arno's heart like a dagger.

Arno still vividly remembered the absolute composure Raygan had displayed throughout their duel.

There had been no hesitation, no opening, no panic.

Even when faced with a spell spiraling out of control, Raygan hadn't flinched. He hadn't shrunk back. Instead, he had stepped forward with absolute, terrifying certainty.

Throughout the entire duel, Raygan hadn't truly been looking at Arno. His gaze had been fixed on something far beyond him.

That gaze was something Arno felt he could never replicate, no matter how hard he trained.

Perhaps that was why Arno couldn't bring himself to believe he would win, even if they were to fight again.

"Father, I wagered my elixir on that duel, and I lost. Please give the elixir that was meant for me to Raygan."

Stern smiled warmly at his son's request.

"Do not worry. I have already compensated Raygan separately."

"...A separate reward, Father?"

"Yes. And from now on, try to get along with him."

"...Yes, Father."

"He is family now, after all. Stay close to him, and see what you can learn from him."

Having fully expected a harsh scolding, Arno left the study with a thoroughly bewildered expression.

"Get along, he says..."

His father wanted him to build a relationship with Raygan.

But could they actually become friends? Arno had never had to initiate a relationship in his life. As the heir of the Benheim family, people had always naturally sought him out first.

Lost in thought, Arno dragged his heavy feet toward the annex where Raygan was staying. When he arrived, he found the maid, Sheryl, sweeping the garden path.

"Sheryl."

"Ah, Young Master. What brings you to this part of the estate...?"

"Is Raygan inside?"

Did she think he was here to cause trouble?

Sheryl looked visibly uneasy, scanning Arno's face before reluctantly confessing.

"Actually... Lord Raygan is currently at the leyline."

"The leyline?"

What business did Raygan have in a sacred sanctuary permitted only to those of Benheim blood?

Though deeply puzzled, Arno didn't press further and turned on his heel.

Later that afternoon, during his magic lessons, Arno noticed that his younger sister, Lunia, was also absent. When he questioned the servants about her whereabouts, one of them tilted his head.

"As for Lady Lunia, I saw her heading toward the leyline a short while ago."

"What?"

Only then did Arno realize that something was highly unusual.

For Lunia to suddenly go to the leyline of all places...

A sudden wave of anxiety washed over him.

Arno rushed toward the leyline, and it didn't take long before he stumbled upon a thoroughly shocking sight.

"Like this?"

"No, a bit higher. Right on the Yanggang acupoint."

"Like this?"

"Yeah, that's perfect."

There was Raygan, completely shirtless, and Lunia, giggling happily with both of her hands pressed flat against his bare back.

No matter how much his father had urged him to get along with Raygan, Arno absolutely could not stand by and watch his ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠precious little sister pawing at some punk's bare flesh.

"You—You! You bastard!"

Arno charged forward, roaring.

It took quite a bit of time to clear up the misunderstanding.