Uchiha Stone Tablet

Seeing the Rinnegan, Itachi summoned a crow, which dropped a feather beside him. Before it could touch the ground, Tsuki teleported onto it, stumbling slightly before Itachi caught him.

"Thanks," Tsuki murmured, a sheepish grin on his face.

"Follow me," Itachi instructed, his tone serious.

They raced through the night, leaping across rooftops and weaving through alleyways until they reached the Uchiha compound. Beyond the main structures, nestled within a secluded grove, stood a shrine.  Itachi led Tsuki inside, their footsteps echoing in the hushed sanctuary. 

A hidden passageway led them to a dimly lit hall. On the far right, Itachi carefully lifted the seventh tatami mat, revealing a concealed room.

"You're here," Shisui's voice greeted them from the shadows.

Tsuki's eyes widened as he saw Shisui standing before a massive stone tablet, his Sharingan activated. But something was different. A four-pointed pinwheel pattern spun within his iris, its chakra pulsing with an unfamiliar energy.

"Shisui, your eyes are different," Tsuki observed, his curiosity piqued. "What are they? They show a different chakra than the normal Sharingan."

Shisui nodded. "Few people know this," he began, his voice hushed, "but there's another stage of the Sharingan."

"Another stage?"

"That's right. And if I'm right, you'll learn all about it here, on this stone tablet." Shisui gestured towards the ancient artifact. "It's a secret tablet, only readable by the Sharingan. However, I believe you should be able to read it too."

Tsuki stepped closer, his Rinnegan focusing on the intricate inscriptions. The symbols seemed to dance before his eyes, their meaning unfolding with startling clarity.  Shisui and Itachi exchanged a look, a mixture of awe and anticipation.

"What does it say?" Shisui asked, his voice barely a whisper.

Thirty minutes passed in silence as Tsuki absorbed the ancient knowledge.

Unseen, a sinister presence lurked within the shadows. A man, his body a grotesque patchwork of black and white, with a jagged, zigzag pattern marring his skin, observed Tsuki from within the very walls of the shrine. His presence was a chilling anomaly, a predator stalking its prey. 

Itachi felt a shiver crawl down his spine. He turned towards the wall, his Sharingan searching for the source of the disturbance. But he saw nothing, only the cold, unyielding stone. 

'I assume after reading this, he now knows about Madara. Tobi won't like this.' Itachi's thoughts swirled with concern, his Sharingan analyzing the situation.

'White, do you feel that chakra? It's the same as...'

'The Sage of Six Paths,' The two communicated telepathically, their bond allowing for silent conversation.

Meanwhile, Tsuki had finished deciphering the tablet.  "Shisui," he began, his voice hushed with awe, "there's much more than just that written here."

He recounted the tale of the Infinite Tsukuyomi, a dream world devoid of war, filled only with victors, peace, and harmony. He explained how the Rinnegan's power, when brought near the moon, would awaken an eye capable of casting this eternal dream upon the world.

"An eternal dream?" Shisui echoed, his brow furrowed. Tsuki nodded.

"But there are warnings too," Tsuki continued, his voice grave. "Warnings about the Sharingan bringing misfortune, and another warning about the Infinite Tsukuyomi itself."

"Someone erased half of the warning and altered it," Tsuki revealed, his Rinnegan scanning the inscription. "The other half says something about the Infinite Tsukuyomi saving the Uchiha clan."

Then, he began to recount the tale etched in stone: the story of the Sage of Six Paths, the Uchiha and Senju clans, and the origins of their conflict. It all began with the God Tree and the Rabbit Goddess, Kaguya Otsutsuki, the mother of all chakra and the mother of Hagoromo Otsutsuki, the Sage of Six Paths himself.

As Tsuki spoke, even Itachi's usually stoic expression shifted, his curiosity piqued by the unfolding narrative. 

"Tsuki," Shisui interrupted, his voice serious, "you said some part of it is altered. Are you sure?"

Tsuki nodded. "It doesn't flow well with the rest of the text," he explained. "One half warns about the God Tree and Kaguya's Infinite Tsukuyomi, while the other speaks of saving the Uchiha clan and bringing an eternal dream. It feels... disjointed."

Shisui stroked his chin thoughtfully, his mind grappling with the implications of Tsuki's words. 

"It seems the one who altered the tablet never expected someone with the Rinnegan to read it," Itachi observed, his voice thoughtful. "They probably didn't possess the Rinnegan themselves, otherwise, they would have erased the first part too."

Shisui nodded in agreement. "In any case, Tsuki," he said, turning to the young boy, "let me escort you back. Staying here too long wouldn't be good for any of us."

"Did I help?" Tsuki asked, his eyes hopeful.

Shisui smiled warmly. "Of course you did."

Tsuki's face lit up, a sense of accomplishment washing over him. He had been helpful to Shisui, his hero. 

With a gentle touch, Shisui activated his Body Flicker Technique, and they vanished from the hidden room, reappearing moments later outside Tsuki's apartment.

"Shisui?" Tsuki asked, looking up at his mentor.

"Yes, Tsuki?"

"Could you teach me more about ninjutsu tomorrow?"

Shisui chuckled. "Don't you already learn at school?"

"Well, it's not enough there," Tsuki explained, his eagerness shining through. "Everything is too easy at school. I only go so I can hang out with Naruto and the others. And you made a promise, remember?"

Shisui's smile widened. "Well, alright then. You're lucky I don't have a mission tomorrow."

Tsuki beamed. "Good night, Shisui."

"Good night, Tsuki," Shisui replied, his voice filled with warmth. 

Shisui watched as Tsuki disappeared into the night, his heart filled with anticipation for the next day's training. He quietly slipped back into the apartment and crawled into bed, his mind buzzing with the secrets of the Uchiha Stone Tablet and the promise of new techniques to learn. He couldn't wait to train with Shisui again. 

-----------------------

As Shisui made his way back to the Uchiha compound, his thoughts were consumed by the revelations Tsuki had shared about the stone tablet. The connection between the Rinnegan and the Sharingan, the possibility of Tsuki being an Uchiha himself... It all swirled in his mind, a puzzle begging to be solved.

'So the Rinnegan is related to the Sharingan after all... Makes me wonder... What if Tsuki is one of us, too? An Uchiha?' But then he recalled Tsuki's words about the Rinnegan being obtained by combining Indra and Asura's chakra. 'So maybe he was given Indra's chakra, or maybe the Sage of Six Paths himself bestowed it upon him?' He shook his head, pushing the thoughts aside for now. 'I can't get too caught up in this. I'll focus on my first theory.'

With renewed determination, Shisui altered his route, heading towards Konohagakure's main hospital. He moved swiftly, his body a blur as he leaped across rooftops. Upon reaching the hospital, he stealthily infiltrated the office of the head doctor. 

The doctor was engrossed in her work, her fingers dancing across the keyboard. Shisui waited patiently, his Sharingan observing her every move. An hour passed, and finally, he made his move.

With a flick of his wrist, he sent a small stone skittering across the floor, landing near the doctor's feet. 

"Huh?" She looked down, startled by the unexpected sound.

In that split second of distraction, Shisui activated his Sharingan and appeared beside her in a blur. He caught her before she could fall, his movements swift and silent.

'I put her in a genjutsu,' he thought, carefully laying her down on the floor. 'She shouldn't be awake for a while now.'

Shisui turned his attention to the computer, his fingers deftly typing in the password. He began searching through the files, his focus narrowed on those related to the Nine-Tails attack. The truth, he was sure, lay buried somewhere within those digital records. 

"Kushina Uzumaki, the previous jinchuriki of the Nine-Tails, gives birth to Naruto Uzumaki, and the Nine-Tails escapes from her seal, causing a wreck for the village," Shisui read aloud, his brow furrowed in concentration. "Many innocent lives were taken that day, and we sent children whose parents died to the Konoha orphanage. Children such as: Akira Matsumoto, Masahira Ando, Naruto Uzumaki, Yusei Takagi." 

Shisui paused, scrolling through the list again and again. "Even here, there's no mention of Tsuki Uzumaki," he muttered, a sense of unease settling over him. "It's like he doesn't even exist. I've checked this list twice now..."

He delved deeper into the files, his Sharingan scanning the digital records with lightning speed. 'Luckily, I've been given more access by Lord Third.' Shisui opened a new file titled "Secrets of the Uchiha."

"Interesting," he mused, "but I don't have the password to access this file. Maybe I can find it in the Hokage's office."

Just then, a knock sounded at the door. "Dr. Asami? I'm coming in," a man's voice announced.  "My shift is ending, so I better go. Let's have dinner tomorrow." The man's voice was tinged with a nervous excitement.

When he opened the door, he found Dr. Asami slumped over her keyboard, fast asleep. With a sigh, he closed the door quietly behind him.

Shisui, perched on a nearby rooftop, watched the scene unfold. 'Tsuki Uzumaki doesn't exist? That doesn't make sense. But there's something else which makes even less sense...'

He turned to the crow perched on his shoulder. "Take this to Itachi," he instructed, tying a small piece of paper to its leg. 

With a final glance at the hospital, Shisui vanished in a blur, heading towards the Naka River. An hour later, Itachi arrived, his Sharingan activated, scanning the area for any sign of his friend. 

"Shisui? You called for me. Sorry, I had to take care of something for my father."

"It's alright, as long as you're here."

Itachi nodded and got straight to the point. "So what's this about? You rarely call me this late."

Shisui relayed everything he had discovered on the hospital's computer.

"I see..." Itachi's voice was grave. "So not only is Tsuki's background covered up, but there's also a possibility that a mysterious child from the Uchiha clan is roaming around."

"Yeah, Arashi Uchiha," Shisui confirmed. "He isn't dead, but he also has no parents on record, and he didn't even go to the orphanage where kids like him were taken."

He paused, his brow furrowed in thought. "Whoever did this was either in a rush, or maybe they were confident that we wouldn't find out. Itachi, do you know of anyone in the Uchiha clan who was giving birth that day?"

"No," Itachi replied after a moment's consideration. "There weren't that many. Only three people were, and they all died with their children during the Nine-Tails incident."

"That's right," Shisui said, his voice heavy. "Fuka Uchiha, Hanami Uchiha... And Hae Uchiha... my mother." He looked down, a frown marring his features.

"I know I'm stretching it," he continued, his voice hesitant, "but do you think..." He trailed off, unable to voice his deepest fear. 

'It's just wishful thinking...'

Shisui shook his head, dispelling the thought. "Nevermind..." He stood up, his resolve returning. "You're an Anbu member, so you can use your higher clearance to find out more about this. You can find out who Arashi's parents were."

"Not that I won't do this," Itachi replied, his Sharingan activated, "but Shisui, why do you care so much about this?"

"I just want to know, that's all," Shisui said, his gaze meeting Itachi's. "I found it too strange that Tsuki could read the tablet, and I want to know more."

He placed a hand on Itachi's shoulder, a reassuring gesture. "Good luck, I'm counting on you." He offered a final wink before disappearing into the night, leaving Itachi alone with the weight of the mystery and the unspoken question hanging in the air. 

(Edited on: 14/9/24)