First, I Need to Beat It a Bit.

In the face of the rampaging surge of immense energy, Cael immediately assumed the lotus position and spun his Chaos Qi to its limits.

The mysteries of the Tai Chi Profound Heaven Heart Method enveloped the energies of the three extreme spirit medicines, beginning to fuse them into a single massive flow.

"Grraaahhh!!"

Opening his mouth here would scatter all the energy. Cael gritted his teeth and began gathering it in.

At first, the wildly swirling energies gradually stabilized under the influence of his Chaos Qi and the Tai Chi mysteries.

And then.

Crack-crack-craaaack—!Snap—Crunch-crunch—!

The pain of bones shattering and realigning, the sensation of veins burning away and new ones sprouting, spread through his entire body.

A smile crept onto Cael's lips.

'Long time no see, this sensation!'

This was the process of huan gu tal tae—one of the things every martial artist in the world yearned for most: the complete rebirth of body and soul.

Even amid the tearing agony, Cael silently gathered his qi and blood, ensuring not a drop leaked or scattered.

How much time passed?

A brilliant light burst from Cael's dantian, and soon all the raging energies were perfectly absorbed. His body fell silent and still.

Whoosh—

'Finally filled it up!'

His Chaos Qi, which had hungered like a bottomless jar, finally felt sated and settled firmly in his dantian.

Not quite up to his Heavenly Demon days, but the durability of his flesh and the volume of his inner energy had reached a satisfactory level.

But...

'The wall I need to surpass with Chaos Qi... is it the Fire Transformation Realm? Or Ultimate Demon?'

He was confused.

Surpassing the peak extreme with righteous qi led to the Fire Transformation Realm beyond. Overcoming the demonic and breaking through the peak extreme led to Ultimate Demon.

But Cael's energy belonged to neither righteousness nor demonhood.

That was why his prior demonic insights didn't apply.

'Does that mean I need to gain new enlightenment?'

"Haha... truly endless."

But there was no need to rush.

No—in fact, Cael felt a spark of competitive thrill and pleasure at pioneering a new path.

The road ahead was still long, and that was a delightful thing for him.

With his vessel perfectly tempered, overflowing was only a matter of time.

For ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠now, this was more than enough.

As he let out a satisfied sigh and rose from his sweat-soaked body—

A chilling, eerie voice slithered directly into Cael's ear—or rather, his mind—from somewhere sinister.

"Hm? What was that...?"

He glanced around, but the secret vault's second floor held only him. Not even a hint of presence.

Cael, having just stabilized his dantian, furrowed his brow and slowly turned toward the source of the bizarre voice.

Step—

In the farthest, darkest corner of the vault stood an ancient altar wrapped tightly in pitch-black iron chains.

Atop it, a longsword emitting a blood-red glow vibrated with an unsettling hum.

'Oh? What's this?'

An ego sword. A blade with a will of its own, the stuff of fantasy legends.

As Cael approached the altar with interest, the chains binding the sword rattled uneasily.

Without hesitation, he ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠reached out and mercilessly tore the chains from the altar.

Clang-crack—!

The moment the chains snapped and the sword's true form was revealed—

The seductive whisper turned in an instant into arrogant, ferocious malice that battered Cael's mind savagely.

Explosive killing intent and foul demonic qi erupted from the sword, trying to ravage Cael's mind in one go.

For an ordinary knight, the sheer malice in that intent would have shattered their mind and stolen their soul—a horrific mental assault.

But Cael just stood there and let out a scoff.

To him, the lord of all demons, trying to devour his mind with demonic qi?

"Thy bluster is laughably pathetic. Daring to speak of demonic qi before me? Come, show me what thou hast."

With those words, a tremendous demonic qi began bursting from the sword.

Frankly, Cael was a bit surprised.

'Oh? Not bad...?'

The sword's demonic qi was potent enough to warrant such bravado.

But...

It had picked the wrong opponent.

The demonic qi was powerful, but not enough to dominate Cael.

Cael gripped the hilt firmly.

And shoved Chaos Qi into it.

Fwoooosh—!

Screams began echoing.

The ego sword's spirited will twisted instantly into agonized shrieks.

'Hm? Does it hurt?'

A will feeling pain was novel, but good for Cael.

"Doth it hurt?"

When Cael asked, the ego sword groveled flat.

"Thy speech is still impudent."

Cael sent more energy.

Cael added to it: one hand infusing energy, the other clenching into a fist to pummel the sword.

Clang—!Claaang—!Clang—!

'This is hilarious. A sword that gets beat when hit?'

Cael found the situation quite amusing.

After dozens of blows, the ego sword's reaction changed.

"Spare thee? Art thou not a sword that isn't even alive to begin with?"

"Oh? Is that so? Then I must beat thee more. The blade looks fine, so I'll melt thee down and use it myself."

Claaang—!

"No matter. A blade that bewitches folk is better off gone from the world."

Klaaang—!

The ego sword grew anxious. Those punches weren't to be trifled with.

A human immune to demonic qi! And the energy this madman exuded devoured demonic qi like a predator.

'N-no!! The sword will break!!'

If the sword broke, so would it.

For the first time since being born a sword, the ego sword felt the terror of death.

And that terror was enough to shatter its attitude instantly.

Its prior arrogance gone, only groveling flattery echoed in his mind.

"Oh? Sincere?"

Cael withdrew his Chaos Qi, smirked, and lightly swung the sword.

The perfect weight settling into his grip, the razor edge still keen after centuries of neglect.

His old martial world sword had been forged of ten-thousand-year cold iron, a famed blade—but no superior to this ego sword in his hand.

'The ego is a minor issue...'

Cael chuckled.

'But that's just entertainment.'

"Thy performance is decent. The edge is keen indeed."

Ting—

Cael said, flicking the blade with satisfaction.

The ego sword purred in delight at the praise, vibrating happily.

"Oh, one of the Three Great Demonic Swords...? Well, doesn't seem that impressive."

But even as it flattered, the sword harbored sinister thoughts within.

'Grr!! Just wait, ye monster. Someday when thou slumberest or falterest, I'll devour thy flesh and make it mine!!'

At that moment, Cael's ash-gray eyes turned to the sword, a chilling smile spreading on his lips.

"Thou... just had irreverent thoughts, didn't thee?"

The sword's vibrations halted abruptly.

"Nay? Seemed thou thoughtest of devouring my flesh."

The ego sword reeled in shock.

No matter how strong, reading the deepest hidden thoughts was impossible.

Yet this monster pinpointed it word for word!

It couldn't know Cael was a master at handling such creatures.

'Their thoughts are predictable.'

"A weapon plotting betrayal deserves the furnace. Dost thou agree?"

No sooner had Cael spoken than tenfold denser, more violent Chaos Qi poured mercilessly along the blade.

Creeeeak—!!

Inaudible, but had it been sound, the agonized mental scream would have rung through the entire ducal residence.

'Oh... enduring Chaos Qi this well...'

Chaos Qi had a flaw: ordinary weapons couldn't handle its vast power.

Thus Cael preferred weakening it or using his body.

But this sword before him could wield fiercer Chaos Qi than any he'd seen.

'Must make it mine. To do that...'

Cael's eyes gleamed.

'First, I need to beat it a bit more.'

Cael spent a good while shaking the ego sword's will with Chaos Qi, delivering a thorough lesson.

Only when steam rose from the sword and its ego was half-shredded did Cael withdraw his energy.

"One more foolish thought, and 'tis the furnace for thee. Understood?"

With the fully subdued ego sword at his waist, Cael felt pleased.

The most satisfying moment since arriving in this fantasy world.

Devouring massive spirit medicines to skyrocket his inner energy, plus snagging a top-tier weapon—what more could he want?

Glancing over the now-empty first and second floors of the medicine vault, Cael smiled and exited.

"Good work."

"Yes sir! Farewell, Young Duke!"

The guards whispered as Cael strode far off.

"Hey... the Young Duke... doesn't he seem a bit different from when he entered?"

"You felt it too...? Even entering, he felt ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠wolf-like... now he's like... a demon—no, like the family head...?"

Daring not call the Young Duke a demon, the guard substituted.

"R-right? The Young Duke's presence was never this overwhelming...?"

The next morning.

The Restis Ducal Residence erupted in chaos.

"F-F-Family Head!! Disaster!!"

Early dawn, Steward Renolt burst into Arjen's office like a madman, face ashen.

Cold sweat poured from the brow of the usually unflappable steward.

Arjen, seated and approving morning documents, looked up with displeasure.

"What racket this morn? So frivolous..."

"Th-the secret vault! The family vault's been ransacked!!"

"What?"