Refinement! Sparring! Leaving the mountain!

As he continued breathing...

Lu You felt a gentle current of air emerge inside him. At his will, it could enter different cells throughout his torso, strengthening their explosive power.

Although there was still very little of this current, and the slightest thought would exhaust it completely.

He was still immensely excited.

The first step was always the hardest. Once his Breathing Style reached Total Concentration-Constant, this current would be produced endlessly with every breath.

Moreover, maintaining his Breathing Style for twenty-four hours-that is, reaching Constant-would also steadily improve his basic physical fitness without him noticing.

"Strengthening the body and supplying energy-that's what a Breathing Style does.

"And while other swordsmen can only use this energy to power their sword techniques, I can convert it into cursed energy and activate cursed techniques."

Only now could Lu You say he lacked nothing.

Even if he left the Demon Slayer Corps now, he could still improve his strength through constant training.

However, his template synchronization would increase very slowly that way. After all, Heavenly Emperor Yuji was an upright person whose ultimate goal was to carry on his teacher Gojo's cherished wish.

To change the world!

And in the world of Demon Slayer, there were two ways to change the world to the greatest possible extent.

The first was to destroy the Demon Slayer Corps, leaving demons to run rampant and all five corruptions to plague the world.

The second was to kill Muzan Kibutsuji and create a world without demons.

So Lu You actually had no choice.

He could only choose the second, since slaughtering innocents was something Yuji Itadori could never accept.

"Giyu, you were right. He possesses an indescribable talent. Perhaps, in the future, he can change the world."

Sakonji Urokodaki was stunned into silence.

Thump!

At the same time, a sharp slap suddenly sounded at the door. Covered in wounds, Tanjiro stood there panting heavily, a delighted smile on his face.

He gave Lu You a thumbs-up and flashed a toothy grin.

The crimson sun had only just risen above the horizon, which meant he had truly completed the trial.

"Lu You... Tanjiro Kamado..."

Looking at the two of them, Sakonji Urokodaki had a vague premonition. He put aside his shock, quickly rose, and helped Tanjiro into the house.

"You have my approval. I will teach you everything I know."

"That's... wonderful! Big Brother You!"

The moment the excited Tanjiro finished speaking, he keeled over unconscious. Exhausted after two days, he finally could not hold out any longer; the slightest relaxation sent him into a deep sleep.

"Yes, it really is wonderful."

Lu You smiled. Outside the window, the morning sun was crimson, warm, and brilliant.

Over the next several months, Tanjiro trained in the mountains. He could now consistently make his way down through the countless traps with ease, and his stamina had improved noticeably.

As for Lu You, he spent these two months focusing on his Breathing Style and could now maintain Total Concentration steadily.

Total Concentration was the first stage of a Breathing Style, marking a genuine level of proficiency. Once one reached this stage, sword techniques could produce all sorts of incredible effects.

"My energy has multiplied several times over, and I've basically mastered all the Water Breathing sword techniques. The first step is always the hardest. Learning other Breathing Styles afterward shouldn't take so long."

He opened the panel.

[Name: Lu You (Invading Body)]

[Psionic realm: peak of the zero tier]

[Divine ability: Astral Transit (red)]

[Strength: 10 Speed: 10 Energy: 8 Spirit: 1]

[Skills: Reverse Cursed Technique-blue, Malevolent Shrine-blue, Comprehensive Weapon Combat-green, Basic Swordsmanship-green, Basic Hand-to-Hand Combat-white, Psionic Manipulation-gray]

[Constitution: Intermediate Physique-green]

[Loaded template: Yuji Itadori (current synchronization: 25%)]

Compared to when he first arrived, his attributes alone had doubled. Besides, this all-around improvement was certainly more than a simple matter of numbers-his energy attribute, for instance.

As his Breathing Style reached Total Concentration, his energy had risen rapidly over this half-year. It could now sustain small expenditures on his slashing cursed technique and Reverse Cursed Technique.

"Does the system judge me as being at the peak of the zero tier based on my total amount of ordinary energy?"

His original body was at the early first tier, yet it fell far short of his current state. Clearly, the system's ratings could only be considered vague boundaries.

Lu You sat inside the house, breathing gently, devouring the surrounding air currents like a black hole.

From his lungs, a warm current spread throughout his body.

With his Breathing Style enhancing him, his explosive power far exceeded ten points. He was much stronger than his original body.

"Perhaps it's about time to leave."

With his mind as clear as a mirror, he continued honing his Breathing Style.

Sure enough, several days later...

"I have nothing left to teach you."

Sakonji Urokodaki held two Nichirin Blades in each hand. His aged voice was steady and powerful as he tossed the Nichirin Blades in his left hand straight to Lu You.

After tracing an elegant arc through the air, the Nichirin Blades landed securely in Lu You's grasp.

Clink! A blade slowly slid from its sheath, its icy edge reflecting the sun's dazzling light.

"Tanjiro, watch carefully."

Sakonji Urokodaki suddenly spoke. Standing nearby in somewhat low spirits, Tanjiro answered in acknowledgment and began concentrating, his dark red eyes wide.

"This is Water Breathing."

His gaze pierced through the Tengu Mask as though he meant to see right through Lu You before him. His breathing was long and deep, as though tides were surging.

Lu You also let out a deep breath and tightened his grip on his Nichirin Blade. Both figures vanished from their positions in an instant!

A speck of dust drifted up.

Then came a fierce collision!

For a moment, brilliant sparks from their clashing blades filled the surroundings, and the ringing of steel filled their ears.

"So fast! I can't see them at all!"

Tanjiro watched the two figures weave past each other in shock. Their rising cuts, slashes, cleaves, and chops were all perfectly placed, and long, narrow streams of water trailed wherever their blades passed.

"Your swordsmanship has begun to take shape, but it's not enough yet. Use Water Breathing!"

"All right!"

At those words, Lu You slammed his toes against the ground. His already formidable base strength became even more outrageous with his Breathing Style's enhancement-utterly ferocious.

At that instant, the yellow earth shook violently, sand and stones bounced into the air, and his figure shot forward.

"Water Breathing-Tenth Form: Constant Flux, Sixfold Strike!"

Sixfold Strike!? And he's starting with the Tenth Form!

Tanjiro suddenly held his breath.

Raging water clung to the blade, tracing graceful curves like a meteor's tail. The figure racing across the ground was impossible to follow with the naked eye.

Damp mist rushed toward them as six water dragons simultaneously closed in around Sakonji Urokodaki. At the head of each dragon, there seemed to be a person.

Dust flew, and the earth shook like thunder.

Real and false, illusory and solid.

"This isn't the essence of Water Breathing... but it suits you very well."

Beneath his mask, Sakonji Urokodaki smiled in gratification.

In Lu You's hands, the originally gentle Water Breathing became as surging and overwhelming as a tsunami.

"Water Breathing-First Form: Water Surface Slash!"

There were no fancy movements. Sakonji Urokodaki's figure simply flickered, and a semicircular blade of water beheaded all six dragons, scattering them into a shower of falling droplets.

"Is this the strength of the former Water Hashira? This is probably above the middle first tier."

Even among the Hashira, he would count as one of the stronger ones!

Lu You retreated several steps, evading that sharp attack, then planted his feet in the ground and steadied himself.

He was just about to continue, but his opponent was already slowly sheathing his blade.

"That's enough, You. Your training is complete."

Sakonji Urokodaki spoke gently. Then he turned toward the dumbfounded Tanjiro.

"Tanjiro, did you see that? When you reach one-third of this level, I'll agree to let you take the Demon Slayer Corps' examination and become one of its swordsmen."

"One-third... I understand. I'll work hard!" Tanjiro was not discouraged in the slightest; he was full of motivation.

In fact, one-third was a very high standard. Urokodaki would not have been so strict in the past.

But after one disciple after another failed the examination and died on Mount Fujikasane, he had begun to doubt himself.

He turned to Lu You, who was still regulating his breathing.

"Your style may be better suited to Stone Breathing, but the Thunder Breathing cultivator lives closer to here. I hear he currently has two successors.

"For your next stop, I'll have Giyu recommend you to him."

Lu You raised an eyebrow. If he remembered correctly, the Thunder Breathing successors were that scumbag senior disciple Kaigaku and Zenitsu Agatsuma from the main cast.