Regarding the method of developing his own Breathing Style, Kuguruma Natsunishi had recently begun to form a vague outline.
The core of a "Breathing" Style did not lie in the sword techniques themselves, but in those two words: the breathing.
Although every Breathing Style was named after various elements, they were essentially mastery techniques over the rhythm and manner of one's breath. By increasing the load on the lungs, heart, muscles, and even the entire skeletal structure, one could push their physical attributes to the human limit in a short burst of time.
The difference lay in the specific focus.
Different Breathing Styles emphasized and reinforced different parts of the body. Taking the Wind Breathing style he was most familiar with as an example: its core lay in improving limb extension and explosive power, particularly strengthening the ligaments and muscle groups of the waist, abdomen, and lower limbs.
Although his mastery of the other Breathing Styles was not as deep, he had gained a fuzzy understanding of them. It was like having a hundred attribute points to distribute among dozens or even hundreds of different branches. While the overall intensity of several Breathing Styles might be similar, the different "pathways" of point allocation resulted in completely different "Sword Intents" and combat styles.
To get even more granular: even when targeting the same body part, different Breathing Styles might adopt entirely different reinforcement schemes.
Based on Kuguruma Natsunishi's own sensations, when Stone Breathing reinforced the heart, it increased the maximum volume after ventricular expansion by about 30% and the closure efficiency of the heart valves by 20%. In contrast, Water Breathing improved heart rate regulation by 10%, ventricular nerve conduction speed by 10%, and maximum ventricular volume by 20%.
As for the parts of the body that could be reinforced, they were too numerous to count.
When he first mastered Water Breathing, Kuguruma Natsunishi had tried the "Fusion" method to create a new style. It was a very simple and crude line of thought: break the rhythm of Wind Breathing into several segments, and then embed or substitute parts of the Water Breathing rhythm into it.
The result was a side stitch.
Not only did it fail to significantly improve his physical attributes like a normal Breathing Style, but it also produced a burning sensation and a feeling of suffocation that almost caused his lungs to spasm.
After that, he continuously adjusted the proportions and transitions between the two styles. He eventually discovered that only when the proportion of one style was compressed to below 10% would the feeling of suffocation and burning significantly decrease.
But... this kind of "Hybrid" breathing was even weaker than using a single Breathing Style directly. Fundamentally, it was nothing more than a degraded experimental product.
After mastering Stone Breathing under Matsuyama, Kuguruma Natsunishi tried another approach: "Tuning."
This involved adjusting the rhythm of a specific Breathing Style. If a Breathing Style was essentially the allocation of points into different branches, that allocation scheme might not necessarily suit everyone's actual situation.
His previous "Degraded Fusion" was a crude merger of Scheme A and Scheme B. The result was that once the human body tried to run the code, it threw an error.
The second scheme Kuguruma Natsunishi attempted was to personally figure out the strength, movement, and frequency of every breathing action—even the specific operational principles of how they functioned when combined. Then, he would adjust them in minute increments, observing the changes and impacts they brought about.
It was much like someone who didn't understand programming trying to adjust someone else's code. It was like reverse-engineering the underlying code based only on the client-side effects, groping for patterns through continuous trial and error, verification, and restoration.
Kuguruma Natsunishi believed this logic was feasible. It was just that the sheer scale of the project and the level of difficulty were far beyond the imagination of ordinary people. Even with Wind Breathing, his highest mastery, he had yet to fully grasp its underlying logic. Perhaps it would only become realistic when a Breathing Style reached Level 4, or even Level 5 and above.
To be honest, if this weren't a game but the real world, Kuguruma Natsunishi would have to admire the founders of the five major Breathing Styles. Every one of them was able to realize a point-allocation scheme that suited them from an ancient breathing technique.
And now, in Mei Nikaido's dojo, Kuguruma Natsunishi had found a third path.
This was one of the rare moments where the cultivator, who usually spent her days soaked in wine jars and sparring matches, showed the reliability of a senior. She offered a different suggestion: don't force yourself to understand every single part of the Breathing Style. If you don't understand the logic of the operating code, then so be it. Just focus on the parts you can understand and adjust or modify those. As for the rest, as long as it can still run, it's fine.
Mei indeed had no experience in creating her own Breathing Style, but her disciple did. A swordsman named Tengen Uzui.
He hadn't even stayed with her for three months before his impatient nature took over, and he insisted on running off early to participate in the Final Selection. He only had a superficial understanding of Thunder Breathing. However, after roughly figuring out some of the principles of the Breathing Style, he relied on his decent talent and his past experience as a shinobi to forcibly cobble together a derivative style: "Sound Breathing."
Yes, a shinobi.
Initially, Nikaido wanted to keep the boy at the dojo a bit longer to temper his personality. After all, even though she was a pragmatist, she wasn't the type to let an apprentice participate in a Final Selection with a high mortality rate after only three months of training.
In the end, she couldn't "persuade" him. Or rather, the attempt to persuade him through force failed.
Nikaido simply couldn't suppress that white-haired youth who constantly talked about things being "flashy" and "festive."
Sound Breathing was certainly strong. But the reason he could suppress Nikaido wasn't because of that. After all, whether it was his superficial Thunder Breathing or the newly created prototype of Sound Breathing, neither could pose a real threat to Nikaido.
Tengen Uzui was able to graduate solely because of his formidable physical fitness and the foundation he built during his time as a shinobi. In the Far East, Nikaido was already taller than the vast majority of men. Yet, that kid was a full head taller than her. He was nearly two meters tall and possessed an extraordinary physique and musculature. Not to mention, the boy had extensive combat experience and swordsmanship skills. Nikaido could tell he had killed people—and more than once.
If it were just that, he might simply be called a natural prodigy. But the brat actually used bombs in the dojo! Small bombs filled with gunpowder that exploded on contact! He claimed it was some kind of "flashy ninjutsu."
He had blown up nearly half of a room in her Den-Shi Dojo on the spot. To this day, the roof was still covered with a waterproof tarp, and repairs were dragging on. Every time she mentioned it, she would grit her teeth in anger.
However, it was indeed a valid path. Kuguruma Natsunishi tried it using his Level 3 Wind Breathing, and it was indeed effective. The system even gave him a face-saving prompt.
[Detected: Breathing Style Prototype under revision]
[Potential Evaluation: Degraded Breathing Style]
[Current Compatibility: 83% (Can be continuously improved)]
[Reminder: Creating a self-made Breathing Style will occupy the character's Exclusive Skill Slot (Unique). Please decide carefully.]
Kuguruma Natsunishi naturally chose to refuse. The game settings allowed only one self-created Breathing Style; there was no way he would make a decision now based on a "degraded" version. Combat skills not recognized by the system could not have points allocated to them or be upgraded.
At this moment, two paths lay before Kuguruma Natsunishi.
Either he could rely on time and high levels to figure out the operating principles of the Breathing Style with the highest compatibility and then create his own. Or, he could directly perform subtractions on the most compatible Breathing Style to quickly polish a simplified version that suited him better.
In player terminology: the former was a "Breathing Style: Custom" that required high levels and high research requirements with no loss in strength. The latter was a "Breathing Style: Custom - Lite" with low entry barriers and low research requirements, featuring high compatibility but lower strength.
As for Kuguruma Natsunishi... naturally, he chose neither!
He wanted to learn all five major Breathing Styles and then use the most compatible one as the skeleton. Once he understood its mechanism or reached an extremely high level of mastery, he would fuse the essence of the other four Breathing Styles into it.
After all, he had already preliminarily mastered four of the five branches: Wind, Water, Stone, and Thunder. He could already faintly sense certain overlapping threads between them.
He even suspected that in a more ancient era, these four—and perhaps all five—Breathing Styles were actually degraded, downgraded versions of a single, stronger Breathing Style with much higher requirements.
He really wanted to try it. After mastering the five major Breathing Styles to a certain extent, he wanted to use them as puzzle pieces to reverse-engineer and restore the lost "Original Breathing" style to its proper form.
Moreover, Kuguruma Natsunishi had a feeling that if he truly mastered all five major Breathing Styles, it would definitely trigger some special event. If he were the game designer or the plot editor, he would definitely design it that way. Collect nine dragon balls to summon a super holy sword, or gather four Shikon Jewel shards to synthesize a pearl...
In that case, it would be perfectly logical for him to gather a set of Five-Element Breathing Styles and fuse them into a single "Primal Chaos Infinite Thunderbolt Unity" Breathing Style.
At least, Kuguruma Natsunishi felt it was perfectly "reasonable."