"Hoo… Hoo…"
Each time Sol breathed out, two streams of white mist escaped from his mouth. The effect resembled the vapor that appeared around his body whenever he activated his Demon Back.
He could feel the changes clearly. His blood circulated faster, his heart rate surged past two hundred beats per minute, and his body temperature stabilized at around thirty nine degrees Celsius. Despite the intensity, the state felt effortless.
The wavelike patterns across Sol's body multiplied. At first they resembled faint ripples, but gradually they surged and expanded like rising tides, forming violent waves that seemed ready to crash. At the same time, an astonishing aura radiated from his body.
The surrounding air grew hotter as the white mist continued to rise from him.
"This full body amplification is pretty interesting," Sol murmured.
He could feel every cell in his body awaken the moment the Mark activated. The amplification it provided was remarkable.
Sol deepened his breathing further. At that moment he resembled a mechanical vacuum pump, pulling in the surrounding air so aggressively that the space around him began to resemble a near vacuum. If he pushed the technique to its limit and burned through his life recklessly, the power might rival or even surpass his Asura Mode.
Still, the side effects were obvious.
Compared to this so called Mark, activating Asura Mode carried far fewer drawbacks. The greater the Mark's power, the heavier the strain and damage inflicted on the body.
It was essentially exchanging life for power. In the history of the Demon Slayer Corps, swordsmen who awakened the Mark rarely lived beyond twenty five.
Behind his tengu mask, Sakonji Urokodaki's eyes widened.
What kind of monster was this young man?
Using a Breathing Technique to pull the surrounding air into a near vacuum was something he had never witnessed before. Not only that, but in just a few days Sol had already grasped the method of activating the Mark. The intensity of the Mark on his body seemed far stronger than those recorded in the past.
If any other Demon Slayer attempted Sol's breathing pattern, their body would likely burst into a cloud of blood.
Sakonji's voice trembled slightly.
"The Mark. This is a trait only possessed by the legendary Marked Swordsmen."
Tanjiro Kamado stopped swinging his Nichirin blade and looked toward Sol in astonishment.
"Mr. Sol, the patterns on your body… what are they?"
"It's simply a manifestation of a Breathing Technique," Sol replied calmly as he glanced at the patterns covering his skin.
Sakonji took a slow breath, trying to suppress the shock in his heart.
"Marked Swordsmen are extremely rare. Every one of them possessed strength far beyond ordinary people. However, awakening the Mark shortens a person's lifespan dramatically and places a terrifying burden on the body."
"You're still young. There's no reason to burn your life for power that fades so quickly."
Sol raised his arm slightly. The Mark glowed faintly as his muscles contracted.
"That's not a problem for me."
"My body is a little special. I can handle this level of strain without difficulty."
"For most people it would be lethal, but for me even keeping it active constantly wouldn't harm my body. Eventually I could make it instinctive."
His expression remained relaxed, showing no sign of strain. However, anyone standing nearby would feel the intense heat radiating from him. Sol's body resembled a furnace, continuously releasing heat, and even the mist from his breath carried enough warmth to sting the skin.
After a moment, Sol reduced the output of the Mark.
The power itself posed no issue for him, but the intense heat and vacuum like pressure would affect Tanjiro and Sakonji if he maintained it unnecessarily.
Sakonji watched the fading patterns silently. Beneath the mask, his expression was complicated.
After a long pause he finally spoke.
"In that case, I will teach you every form of Water Breathing."
Sol shook his head.
"You should focus on teaching Tanjiro. Once the plan to hunt Muzan Kibutsuji begins, I'll be leaving here anyway."
In his opinion, the sword forms of the Demon Slayer Corps actually restricted the potential of Breathing Techniques. It was unfortunate. Such an interesting system was limited by the use of swords.
Besides, a Nichirin blade could hardly compare to Sol's hardened physique.
Sakonji remained quiet for a moment before nodding slowly.
"I understand. But Tanjiro still requires more foundational training."
Sol glanced toward Tanjiro, who was drenched in sweat.
"His talent is good. He just hasn't received proper systematic training yet."
Over the following days, Sol observed Tanjiro's practice while continuing to study the mechanics of Breathing Techniques.
"Mr. Sol, am I swinging the blade correctly like this?"
Tanjiro raised his wooden sword. Sweat dripped from his face after hours of training.
Sol stepped forward and adjusted Tanjiro's posture slightly.
"Relax your wrist more. Let the power travel naturally through your arm."
Tanjiro followed the advice and swung again. His eyes widened.
"It really is smoother now!"
Nearby, Sakonji watched silently. Beneath his mask, his expression grew more complex.
Even when it came to training disciples, could he still not match this man?
Anyone who became Sol's opponent would likely face a very unfortunate fate.
On the morning of Sol's fourth day at Mount Sagiri, he stood at the edge of a cliff overlooking the forest below. The rising sun pierced through the clouds, casting golden light across his figure.
After several days of experimentation, he had successfully merged Breathing Techniques with his own physical abilities, forming a unique combat style.
"Mr. Sol!"
Tanjiro's voice called from behind.
The boy ran toward him while holding his katana, sweat still fresh on his forehead from morning training.
"Mr. Sakonji said I should come find you for sparring."
Sol turned around and noticed the new scratches on Tanjiro's arm. A small smile appeared on his face.
"Alright. Let's see how much you've improved these past few days."
Tanjiro inhaled deeply and took his stance. His eyes sharpened as his breathing steadied according to Sakonji's teachings.
With a sudden step forward, he swung his wooden sword in a swift arc.
Sol did not move from his spot. He simply tilted his body slightly and avoided the strike.
"Your movements are too obvious," Sol said calmly. "And your breathing still lacks continuity."
Tanjiro nodded and adjusted again.
This time his movements flowed more smoothly. The wooden sword sliced through the air repeatedly with sharp whooshing sounds.
Sol still did not move his feet. He avoided every attack with minimal movements of his upper body.
"Good," Sol said with approval. "You're improving quickly."
"But you're focusing too much on attacking. Always keep your defense in mind."
Determination flashed in Tanjiro's eyes.
"Again!"
They continued sparring on the cliff for the entire afternoon. As the sun climbed higher, Tanjiro's clothes became soaked with sweat, yet his eyes only grew brighter with each exchange.
When the sun began to set, Sol finally raised a hand.
"That's enough for today."
"You've mastered the fundamentals. What you need now is real combat experience."
Tanjiro lowered his wooden sword and bowed deeply.
"Thank you for your guidance, Mr. Sol!"
Sol waved casually.
"Go get some rest. Training continues tomorrow."
As Tanjiro walked away, Sol watched his back with a faint smile.
"My transmigration value went up a little."
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