Reincarnation as Lower Rank Five in Demon Slayer

In the Natagumo Mountains, in front of a two-story house with an A-frame roof, Li Lei sat quietly in the courtyard, looking at the Nichirin Blade in his hand, his thoughts returning to the tragic scene he had endured the day before.

Suddenly, I felt a faint pain in my lungs, which I used for breathing. I reached out and touched my chest, only to find that it was just a hallucination.

Li Lei, who was in the courtyard, breathed a sigh of relief and chuckled softly.

"The backlash damage from switching breathing techniques is really severe for demons."

"However—I was too careless during yesterday's breathing exercise. I dared to switch breathing techniques halfway through. I must not do that today. I must be careful."

He silently reflected on his actions.

"But it also shows that my cultivation direction is correct, and the way to overcome sunlight is in there."

This can be known from one's memories of past lives.

All the breathing techniques are inferior imitations of the Sun Breathing Technique, because the powerful Sun Breathing Technique is almost impossible for anyone to learn except its creator, Yoriichi Tsugikuni.

Hundreds of years ago, the Demon Slayer Corps members, unable to learn the Sun Breathing technique, had no choice but to create the five basic breathing techniques—Water, Lightning, Fire, Rock, and Wind—under the guidance of Yoriichi Tsugikuni, which were suitable for ordinary people to learn.

Each of the five basic breathing techniques possesses some characteristics of the Sun Breathing Technique.

For example, Water Breathing possesses the endurance of Sun Breathing, Lightning Breathing possesses the speed of Sun Breathing, and Rock Breathing possesses the power of Sun Breathing, etc.

The five basic breathing techniques are easy for anyone to learn, but how well one can master them depends on their talent and effort.

However, one point is very important: although you can learn many breathing techniques, you must never turn them into other breathing techniques when you are using them.

The reason is that the sudden change in breathing techniques during combat can severely damage the lungs of ordinary people because they cannot withstand the sudden change.

Li Lei has a deep understanding of this.

Therefore, generally no one learns more than two breathing techniques. After all, even if you learn one, you can only use it in battle, and learning more will inevitably prevent you from mastering them all.

On the contrary, it would slow down the rate at which ordinary people become stronger, which is unacceptable for the Demon Slayer Corps, which constantly eliminates evil spirits and faces danger.

Because human lifespan is limited, even if someone lives to 90, their robust health will only last for a few decades.

Of course, the protagonist in the original work is an exception, as he can learn the Sun Breathing Technique.

However, as a ghost, Li Lei had a bold idea in his mind.

Since each of the five basic breathing techniques possesses certain characteristics of the Sun Breathing Technique, they can all be regarded as serious deficiencies of the Sun Breathing Technique.

Once you learn the five basic breathing techniques and overcome the backlash from switching between them, you'll have essentially learned a simplified version of the Sun Breathing Technique.

By doing this, one's physical condition will inevitably change as one overcomes the backlash from different breathing methods, making it possible to learn the Sun Breathing Method.

Finally, all that's needed is to find a way to obtain the simplified version of Sun Breathing, Hinokami Kagura, from the protagonist and learn it.

After learning Hinokami Kagura, one's body will inevitably change and evolve through prolonged use of the simplified version of Sun Breathing.

This reduces or even neutralizes the harm the sun can cause to itself.

At that time, I must strike a pose under the rising sun in front of Muzan, and say something to anger Muzan under his shocked gaze.

Just imagine Muzan's angry expression.

"Hehe—just thinking about it makes me excited."

"However—all of this depends on the success of my own ideas."

Forget it, I don't want to think about it anymore. I should get back to cultivating!

Li Lei stopped his fantasies, put down the Nichirin Blade in his hand, and began to practice the transformation of his breathing technique.

He started by practicing the Water Breathing Technique, and after a while, he switched to the Thunder Breathing Technique. After switching from Water Breathing to Thunder Breathing, Li Lei suddenly felt discomfort in his lungs.

But Li Lei didn't stop there; instead, he worked even harder, constantly changing his breathing techniques.

One minute, two minutes, three minutes... More than twenty minutes later, as the time for changing breathing techniques increased and the pain in his lungs intensified, Li Lei's lungs finally could not withstand the backlash from the change in breathing techniques and began to be injured and bleed.

However, as a demon, the lungs were immediately repaired by its powerful regenerative abilities as soon as they were damaged.

And so, Li Lei kept practicing the breathing technique, kept switching between different breathing techniques, and kept adapting to the backlash from these changes.

Gradually, thanks to Li Lei's tireless efforts, the backlash from constantly changing his breathing techniques began to weaken, and the frequency of lung injuries began to decrease.

Under Li Lei's powerful regenerative abilities, his ghostly body slowly changes and evolves as it is constantly injured and repaired.

As a demon, Li Lei, without the knowledge of the Demon King Muzan, relentlessly pursues his dream of living longer under the sun.

Meanwhile, in the Infinity Castle, Muzan's experiment with the blue spider lily failed once again.

In his disappointment, Muzan's veins bulged, his face contorted in a ferocious expression, and an immense pressure erupted from his body.

"Damn it, I failed again! Where is the Blue Spider Lily?"

"For hundreds of years, why haven't we found the blue spider lily?"

"There it is!!!" /?◥?i_?◤?\

The enraged Muzan's immense pressure instantly swept across the entire area, shattering the tables, chairs, and experimental equipment around him, and leaving the house riddled with cracks.

"Narume."

After calming down, Muzan called out to Nakime.

"Yes, sir."

Upon hearing Muzan's cry, Nakime instantly appeared beside him.

"Let's go out for a walk to clear our heads."

Muzan said in an icy tone.

"Yes, my lord"

Upon hearing Muzan's order, Nakime immediately used her Blood Demon Art to teleport Muzan and herself out of the Infinity Castle.

The disappearance of the two demons left the Infinite City silent.

……