On the other side of the world, a colossal entity floated within the vast ocean. Like a moving island, it followed a predetermined path, gradually drawing closer to the coast of the Land of Frost.
The sea breeze swept past, carrying the cries of seagulls into the sky.
Turtle Island, The Training Grounds.
Beneath the massive mural in the underground palace, inside the now-open Pitch-Black Door.
Ren Uchiha sat cross-legged at the edge of the altar, hands resting on his knees, eyes closed. The expression on his face grew increasingly solemn.
In the next instant, the unique natural energy flowing within the secret chamber formed a vortex, slowly converging into the chest of the youth.
Shua!
As a pair of deep purple snake-slit pupils snapped open, lines of subtitles manifested before his eyes:
[Based on your understanding of Yin Release and your continuous three-day observation of the flow of Yin-attribute natural energy within this room, you have discovered a hidden inheritance and gained insight.]
[You have mastered: Sage Art: Yin Release Wind Cutter (-, Entry Level)]
[You have mastered: Sage Art: Yin Release Phantasm (-, Entry Level)]
[As your understanding of Yin Release deepens, you may be able to fuse Yin Release with other attributes to create new Kekkei Genkai or even Kekkei Tota.]
"Phew..."
Ren exhaled a long breath. The deep purple faded from his eyes, revealing the scarlet three-tomoe Sharingan beneath.
"Because the destruction happened too quickly, a complete inheritance couldn't be left behind. Ultimately, they had to use this clever method to preserve the Sage Arts of the ancient era."
"Compared to lightning, fire, water, or earth, only 'Wind'—which can have its flow fixed by architectural structures—could cross a thousand years to appear before me."
"Is that why it's Sage Art: Yin Release Wind Cutter?"
Ren raised his hand, the veins around his eyes bulging as he formed a single 'Dragon' seal. In the next moment, a visible purple wind blade manifested above his other palm.
Ying Release creates form out of nothing; Wind Release cuts through all things. The hallmark of this combined Sage Art was its casting speed—fast enough to stifle an opponent—coupled with extreme cutting power. This was a technique just one tier below the Sage Art: Yin Release Thunder Dispatch used by Six Paths Madara.
As for further progression...
"Yin Release Thunder Dispatch requires mastering Purple Electricity first, then combining it with Sage Arts. Meanwhile, the Sage Art: Storm Release Light Fang used by Madara—which was sharp enough to cut a Truth-Seeking Ball—requires fusing Lightning and Water into the Storm Release Kekkei Genkai, then elevating it to a Kekkei Tota with Yin Release, and finally infusing it with Senjutsu."
Ren dispersed the purple blade with a thought.
"In other words: Sage Arts + Yin-Yang Release + Kekkei Genkai is the minimum requirement to trade blows with a Six Paths-level enemy."
"The Sages of the Post-Ancient era didn't have that capability. They fought Kaguya using rudimentary, single-attribute techniques like Wind Cutter and Thunder Dispatch."
He looked at the magatama on the altar and shook his head. "No wonder Kaguya suppressed them so easily."
The altar was carved with ancient drawings: a group of 'Sages' in tears, wielding Sage Arts of various colors, charging toward a figure silhouetted against a crimson moon with nine tomoe.
This touched upon a piece of ancient history told by Black Zetsu. After Kaguya consumed the fruit of the Divine Tree, the natives of the Shinobi world had no power to resist. She unified the lands of Ancestors and That, and everyone was hung from the tree.
However, after unification, her control slipped. She frequently had to suppress rebellions. Ren called this the Post-Ancient Era.
During this time, Hagoromo (the Sage of Six Paths) learned from a traveling merchant that the Land of That was rebelling. Kaguya, the 'Tyrant,' went to suppress them. This allowed Gamamaru to lure Hagoromo to the Divine Tree, where he saw the corpse of his love, Haori—the catalyst for his awakening.
Those rebels were people who had been hung from the tree, had their memories wiped, and were released to repopulate. They managed to distract Kaguya because the Divine Tree had already altered their genetics, granting them chakra. The animals, seeking revenge against Kaguya, combined the Sage inheritances of the pre-tree era with this new chakra to create Senjutsu Chakra, giving humans a fighting chance.
Now it seemed clear: Turtle Island, the Falls of Truth, the headless statues, and this soul-probing room were pure natural energy mechanisms left by a 'True Sage' from the Ancient Era. The buildings and the cover-up murals were products of the era that followed. Under the guidance of animals, humans rediscovered the waterfall, built this room, and left behind their techniques and a shameful history.
Because only a son could defeat Kaguya. These 'Sages' were merely bait—sacrifices meant to lure Kaguya away so Hagoromo could grow strong enough to face her.
Ren stood up from the altar and sighed. He had explored the entire island, including the room where Naruto and Bee would eventually master their Tailed Beast forms. Sage Art: Yin Release Phantasm was the Genjutsu guarding this door; it was no match for his eyes.
While he hadn't found a direct way to upgrade his Sage Form, his current progress already exceeded that of the island's past Sages. As Orochimaru had said, this deepest room had little value for him beyond helping master foreign energies.
However, he didn't leave empty-handed. After he analyzed the techniques and absorbed the massive amount of Yin-attribute natural energy here, the barrier around the altar vanished.
The magatama lay exposed. When Ren's hand touched it, a new line of text appeared:
[You have obtained: Divine Artifact—Yasaka Magatama (Original).]
[Divine Artifact—Yasaka Magatama: A precious object that witnessed the fall of an Emperor, the revenge against a Tyrant, and the founding of the Ninshu. It passed through the hands of the Emperor of the Land of Ancestors, Haori, and the Sage of Six Paths, fulfilling Gamamaru's revenge before being buried here.]
[The Divine Might has been extracted by the Sage of Six Paths and fused into his bloodline, becoming the summoning spirit-tool for the Susanoo (Stage 3, Armored Susanoo).]
[A bloodline owner holding the physical artifact can use it to summon the artifact early and unleash its maximum potential.]
"So that's how it is..." Ren's expression sharpened.
The jade pendant worn by the Emperor was the same red jade later worn by Haori. It fell into Hagoromo's hands at the roots of the Divine Tree and became a weapon against Kaguya. Hagoromo then fused that power into his Susanoo, passing it down through the bloodline.
This explained why every high-level Uchiha 'Gundam' pilot could manifest a Yasaka Magatama at Stage 3.
"I used to wonder why there were so many 'Divine Artifacts' that every Susanoo had one. This is the root of it all." Ren weighed the jade in his hand, marveling at it before hanging it around his neck.
"Well, it's mine now!"
Having gained everything Turtle Island had to offer, Ren stepped out of the palace. His previous weakness was gone, replaced by eyes that shone with brilliant light.
The sun glittered off the ocean surface. Seagulls soared. The damp sea breeze tossed his long hair. Watching the coast of the Land of Frost grow larger on the horizon, Ren curled his lips into a smile.
"Alright then."
"Land of Lightning... I'm here!"