NARUTO : REBORN WITH HETERO CROMATIC EYES

As Wiz explained her answer, Ryuga was stunned to learn he had been using a higher form of energy—mana—all along, without even realizing it. His mind raced with questions. 'Wiz, what do you mean by a higher form of energy? You never mentioned this until now.'

'ANSWER: CHAKRA IS A FOREIGN ENERGY PRESENT IN THIS WORLD; HOWEVER, MANA, OR NATURAL ENERGY, IS NATIVE TO THIS WORLD. CURRENTLY, CHAKRA ACCOUNTS FOR ABOUT 90% OF THE ENERGY IN THE ATMOSPHERE, WHILE MANA ONLY ACCOUNTS FOR AROUND 10%. BECAUSE OF THIS, MANA IS RARE AND LESS ACCESSIBLE, BUT ITS POWER FAR EXCEEDS THAT OF CHAKRA.'

Ryuga absorbed the information slowly, intrigued by this new understanding of energy in his world. 'So, you're saying that I can use mana directly because of its compatibility with chakra?'

'CORRECT. YOUR BODY CAN HANDLE MANA BECAUSE OF THE HASHIRAMA CELLS IN YOUR BODY, WHICH HAVE A UNIQUE ADAPTATION. THESE CELLS INTERACT WITH MANA WITHOUT RELYING ON CHAKRA, ALLOWING YOU TO ACCESS ITS POWER WITHOUT TURNING INTO STONE, A COMMON SIDE EFFECT FOR MOST SHINOBI WHO ATTEMPT TO USE IT.'

Ryuga's thoughts sharpened. He remembered tales from the anime and manga—Naruto, Jiraiya, and even the Sage of Six Paths had used natural energy to enter Sage Mode. Now it made sense: mana, this natural energy, was the power behind Sage Mode.

His curiosity deepened. 'Why can only Hashirama's cells directly interact with mana? Does that mean I can only use mana through chakra, or can I learn to use it on its own?'

'HASHIRAMA'S CELLS DEVELOPED THIS ADAPTATION THROUGH LONG-TERM EXPOSURE TO MANA, EVOLVING TO USE IT WITHOUT DEPENDENCE ON CHAKRA. AS FOR YOU, YOUR BODY STILL RELIES ON CHAKRA, SO MANA CAN ONLY BE USED AS A SUPPLEMENT. EVEN IF YOU TRIED, YOUR BODY LACKS THE NECESSARY ADAPTATION TO SUSTAIN MANIPULATING PURE MANA ALONE FOR AN EXTENDED PERIOD.'

Ryuga was amazed, gaining insight into why Hashirama was so powerful. His ability to continually use Sage Mode was more than just skill; his cells had adapted over time to use mana without chakra, which explained his advantage over others, including Madara Uchiha.

'So, adapting to mana makes you more powerful. Could we, I don't know, speed up the adaptation process?' Ryuga asked, envisioning a path to new power levels.

'SUGGESTION: IT IS RECOMMENDED TO FIRST LOCATE OR CREATE STABLE SOURCES OF MANA, WHICH WILL SUPPORT A SUSTAINED ADAPTATION PROCESS. WITHOUT SUCH RESOURCES, YOUR ABILITY TO USE MANA EFFECTIVELY WILL REMAIN LIMITED.'

Ryuga considered Wiz's suggestion. Gathering stable sources of mana would be challenging, but the potential to harness this potent energy was worth the effort. Deciding to follow Wiz's advice, he instructed her to begin preparations for future adaptation.

He then exited "Thought Acceleration" mode and tuned back into Shisui's explanations on fire chakra transformation. Shisui had a meticulous approach, covering every step in detail. With "Thought Acceleration" capable of a hundred times speed, Ryuga's mind processed everything quickly, making it easier to replicate Shisui's methods.

Once Shisui finished explaining, Ryuga started his fire chakra transformation training under his guidance, practicing the basics for over an hour. By the time he went home, Ryuga's mind buzzed with the lessons, his body exhausted but satisfied.

At home, he prepared a simple meal and, after eating, resumed his chakra nature transformation training. This time, he experimented with combining mana and chakra, adjusting their ratios to see how it would affect the results.

Almost instantly, Ryuga's chakra transformed into flame, smoother and faster than before. With each try, he refined his technique, finding that blending mana with chakra significantly enhanced the effectiveness of the transformation. He applied this to other elements, and each attempt succeeded just as smoothly.

As he practiced, Ryuga discovered the subtle difference between chakra and mana. With Wiz's sub-skill "Quantum Manipulation," he only needed a single mana particle to guide chakra into different elements. Once he established the transformation pattern, Wiz recorded it, allowing him to convert chakra into the element of his choice without additional effort.

After completing his training for the night, Ryuga went to bed, making sure to rest adequately before school the next day.

The next few days fell into a steady routine. Each morning, Ryuga attended classes and spent his afternoons training with Sasuke. Sometimes, Itachi or Shisui would join them, depending on their schedules. The sessions began with simple drills, yet even these basic exercises helped Ryuga sharpen his skills and observe Sasuke's progress.

In the first month, he focused on the basics of chakra transformation, pushing himself through repetitive training under Shisui and Itachi's watchful eyes. They seemed hesitant to teach him more advanced techniques at first, so Ryuga kept his requests minimal, content to let them assess his commitment.

Finally, after three weeks of continuous practice, Ryuga managed to successfully transfer his chakra into fire nature. The first flicker of flame marked a breakthrough, and with that, Itachi decided he was ready to learn a new jutsu.

Itachi demonstrated the Great Fireball Jutsu, performing the technique with remarkable control. The large ball of flame roared through the training field, leaving Ryuga awed and eager to master it.

"Can you show me different variations of the Fireball Jutsu?" Ryuga asked. Itachi, who was usually reserved about teaching multiple techniques at once, seemed to recognize Ryuga's determination and agreed without hesitation. He demonstrated variations like the Great Fireball, Dragon Fire, Phoenix Flower, and even some lesser-known techniques within the Uchiha repertoire.

Each day, Ryuga practiced the fire jutsu under their supervision, not asking for anything else, even as he memorized the techniques. In the following two weeks, he diligently refined his Fireball Jutsu, steadily increasing his control and power without pushing for other lessons. His patient approach seemed to earn him respect from Itachi and Shisui.

The months slipped by as Ryuga honed his skills, developing his control over kunai and shuriken as well. He consistently attended school, his focus evident in his studies, though he purposely kept a low profile, securing a place in the top twenty during exams instead of aiming for first.

Meanwhile, Ryuga continued to observe his classmates, particularly Isagi Youjiro, who consistently held the top spot academically. Keeping a close eye on Isagi's progress, Ryuga remained aware of the competition while avoiding unnecessary attention.

As for his training with the Uchiha brothers, it had been four months since he began practicing with them, and he had learned an array of techniques. He mastered the basics of the Shadow Clone Jutsu, Transformation Jutsu, and Body Flicker Jutsu. Yet, he made sure only to display the simplest form of the Shadow Clone Jutsu during their sessions. Unknown to the others, he had already refined his skills, reducing hand seals and achieving control at a level where he could perform these techniques with a single sign or none at all.

Over time, Ryuga's relationship with Shisui deepened. Shisui often treated Ryuga like a younger brother, occasionally surprising him with treats after particularly rigorous sessions or gifting him a fresh set of kunai or shuriken. Since Ryuga had been relying on worn-out weapons provided by the village, these small acts of kindness felt significant.

During one of their conversations, Shisui offered to lend Ryuga some money, but Ryuga declined politely. He explained that he preferred to ask if he ever truly needed something. His pride and independence had earned Shisui's respect, and their bond strengthened as they continued to train together.

One day, Ryuga noticed Shisui's straight katana, a weapon he had admired. Out of curiosity, he asked if he could borrow it for training. Shisui responded with a smile, explaining that the katana was crafted from a special metal in the Land of Iron, and that it was more than just a weapon—it was a partner that had supported him throughout his shinobi life. Though disappointed, Ryuga accepted the explanation, understanding the deep bond Shisui had with his weapon.

As time passed, Ryuga continued refining his skills, making remarkable progress in his techniques. His fireball, transformation, shadow clone, and throwing techniques reached new levels of proficiency, though he kept his true capabilities hidden.

Yet, recently, Shisui had been absent from their sessions more frequently, and Ryuga noticed subtle changes. During one rare training day, Ryuga observed that Shisui seemed distracted, his mind elsewhere, with wounds scattered across his arms and face.

Unable to ignore his concerns, Ryuga finally asked, "Shisui, is something wrong? You've missed a lot of training recently, and… you look hurt."

Shisui ruffled Ryuga's hair with a smile, though his eyes held a hint of something darker. "It's nothing, Ryuga. Missions are getting tougher, that's all. But don't worry—I'll take care of everything so everyone can live in peace."

Ryuga caught the underlying tone in Shisui's words. Though Shisui had never shared these kinds of thoughts before, Ryuga sensed the weight of his struggles and felt a growing unease. He knew what was coming—the day Shisui would fall victim to Danzo's ambitions was drawing closer.