Nirvana

This was also related to some things Ye Mu had discovered while developing his Devil Fruit abilities.

Although Ye Mu was not a scientist like Vegapunk, he was an ability user who had benefited from nine years of compulsory education and higher education on Earth, as well as from his knowledge of the plot.

By carefully sensing the specific changes in his body while using his Devil Fruit, combined with comparing notes with Enel, he was still able to discover quite a few interesting things.

Of course, since both of them were Logia ability users, everything they discovered was related to Logia abilities.

For example, while using his Devil Fruit ability, Ye Mu discovered that a Logia Devil Fruit's ability to create its element was not limitless.

Simply put, taking Ye Mu as an example, although he possessed the Flame-Flame Fruit, that did not mean he could produce an infinite amount of flame through it.

The process was more like there being a certain substance inside his body.

Combining this with the descriptions in the story, Ye Mu named it the Lineage Factor.

This Lineage Factor could convert the physical energy in his body into flame. The more flame it converted, the more energy it consumed.

This also explained why the stronger a person's body was, the stronger their Devil Fruit ability would be.

It seemed like a flaw, but it actually confirmed that the superiority and inferiority counters between Devil Fruits were not absolute. As long as the user was strong enough, they could completely ignore such restraints.

It also provided a path for advancing one's Devil Fruit ability, even all the way to awakening.

For another example, Ye Mu discovered that the essence of a Logia user becoming elemental was not turning into an element to evade attacks, but controlling the flow and transformation of their body.

Simply put, after transforming their body into an element, a Logia user could flow and change their body freely within the element they had created, just like water.

This might sound obvious, but it confirmed one thing: during the process of becoming elemental, a Logia user did not actually lose their physical form. They were merely like water, hiding their body within the element by changing its form, making it impossible for physical attacks to harm them.

This also explained why Haki could harm Logia users.

A Haki user could use Observation Haki to locate the physical body of a Devil Fruit user during their elemental transformation, then use Armament Haki to seize them.

This might also explain why some Logia users did not fear Armament Haki. If one could not find the location of the user's physical body, then even with Armament Haki, one could not seize the Logia user's true body.

As for how Armament Haki users seized elementalized users who flowed like water, Ye Mu could not know yet because he had not awakened Armament Haki.

However, Ye Mu had a vague guess. There were only two ways to seize water: one was to turn the water into ice, and the other was to use water to seize water.

Ye Mu believed that the two points he had discovered earlier were characteristics generally shared by Logia Devil Fruits, with the obvious exception of the Dark-Dark Fruit.

The next interesting point Ye Mu discovered, however, might only apply to Devil Fruits like the Flame-Flame Fruit, the Rumble-Rumble Fruit, and the Glint-Glint Fruit.

These three Fruits had one common characteristic: the elements they created through elemental transformation—such as flame, lightning, and laser beams—were pure energy. Unlike other currently known Fruits, such as ice, magma, sand, and smoke, they did not possess an absolutely tangible physical form that could be touched.

Aside from making these three types of fruit users even harder for Haki to capture, this also gave Ye Mu a new idea.

This was also related to Ye Mu wanting to personally develop the Six Powers.

Since he had come to the world of One Piece, before mastering Haki, the Six Powers were such useful martial techniques that the sooner he mastered them, the better. Besides, wasn't there a rumor that the Six Powers were the basic version of Haki?

In the end, however, Ye Mu gave up. It was not that he could not develop them, but after thinking it over carefully, he realized there was no need to waste his precious time on them.

That was because he discovered that, for the time being, the Six Powers were somewhat useless to him.

The Six Powers consisted of six techniques: Soru, Tekkai, Kami-e, Geppo, Rankyaku, and Shigan.

But after thinking it over carefully, Ye Mu realized that aside from Soru's instantaneous movement being somewhat useful, his Devil Fruit already provided him with the other five techniques.

First, Tekkai and Shigan were completely inferior to elemental transformation. Ye Mu could use his Devil Fruit to produce the same effects as Rankyaku and Shigan, and as for Geppo, he could fly using the Flame-Flame Fruit.

As for Enel, there was even less need to mention him. No matter how fast Soru was, could it really be faster than lightning?

In some respects, Enel's Rumble-Rumble Fruit was more versatile than Ye Mu's Flame-Flame Fruit.

So rather than spend a great deal of time on these somewhat useless martial techniques, he might as well spend it on developing his Devil Fruit and strengthening his body. Once he reached the Blue Sea, wouldn't it be better to simply snatch them from CP9?

However, although he no longer needed to develop the Six Powers, thinking about them reminded Ye Mu of another extremely interesting ability: Life Return.

Life Return had first appeared in the hands of the lion-like man from CP9 at Enies Lobby. Through the ability of Life Return, he could freely control any organ on his body, such as his hair, internal organs, limbs, and muscles.

Furthermore, in the later parts of the story, Life Return was shown to have effects such as rapidly digesting food, recovering physical strength, storing energy, and accelerating wound healing.

This gave him an idea. Could he use Life Return to transform his body and make it grow stronger and stronger?

Although Ye Mu had made his body countless times stronger through arduous training, he also understood that compared with those monsters, he was still far behind.

The problem was that he did not know Life Return, nor did he know how to learn or master it.

But he had the Flame-Flame Fruit.

That was also why he had mentioned earlier that the Flame-Flame Fruit, the Rumble-Rumble Fruit, and the Glint-Glint Fruit were special.

They could transform their users' bodies into pure energy, with the only difference being how that energy manifested.

Then, could he slightly modify this ability and turn it into another form of Life Return?

After all, although Logia users could not yet change external matter and convert it into an element—it was still uncertain whether that was possible—they could control their own bodies. This naturally included the food they ate.

Thus, after getting this idea, Ye Mu spent a full three years carefully experimenting step by step. In the end, he finally developed it.

He named it Nirvana.