The reality of the Naruto universe, like many other universes, is composed of four main dimensions: three of space and one of time. This set is called the material plane. Above these four dimensions exists a fifth dimension that groups together different parallel realities and timelines, commonly known as the multiverse.
If one were to observe Naruto's multiverse from the outside, they would see a huge bubble whose interior contains complex cosmic structures formed by main realities with multiple converging timelines that extend infinitely like tentacles. Some of these lines merge with each other or with the timelines of another reality, are destroyed by some phenomenon, or reintegrate with their respective main reality.
In each main reality, hidden between the fourth and fifth dimension, there exists an intermediate space whose inhabitants called the Plane of Transcendence.
This plane is a plane in the literal sense: a flat world, without curvature, whose size exceeds that of several galaxies combined. It has no climate, seasons, or natural life. It exists only for one purpose: to contain those who can no longer remain in the material plane.
When a being in the Naruto universe reaches a level where they can easily destroy a galaxy, their presence becomes incompatible with common reality. Such beings break the shackles of their lifespan, becoming eternal beings.
A couple of decades ago, in the transcendent plane corresponding to the same reality where Noah originated, an event shook the usually quiet and monotonous transcendent plane. Shibai Ōtsutsuki, the ancestor of the Ōtsutsuki clan, finally transcended, shedding his physical body and becoming a being made entirely of chakra.
To the horror of Shibai and the various beings inhabiting the area where he appeared, terrifying auras covered the place, fixating on him. The Devouring Forest, a forbidden region that almost no one spoke of and no one dared to explore, stirred upon sensing his presence. It was located hundreds of thousands of light-years from the place where Shibai appeared. Still, countless auras awakened, filled with hostility and murderous intent, all focused on him.
Three of those auras shot off, crossing the void in his direction.
Shibai, on the other hand, did not hesitate and with a movement of his hand, created a spatial rift in front of him, into which he entered, escaping his pursuers.
Since that day, the Devouring Forest has never been silent again. One by one, more and more auras emerged from its interior, going out to hunt the Ōtsutsuki God.
---
In the present day, deep within the Devouring Forest:
This forest was constantly covered by a dense layer of dark fog that prevented outsiders from seeing what was happening inside.
In the deepest part of the forest, a hundred imposing, somber-looking trees were planted in an orderly manner. Each rose like a colossal tower, their trunks cracked as if time had broken them, and their twisted, leafless branches stretched toward the sky like claws.
At the exact center of the forest, surrounded by these withered titans, stood a tree with a majestic appearance. Its leaves, silver like mercury, trembled slightly without wind. Its trunk had a huge vertical crack, from which flashes of silver light occasionally emerged. The faint glow coming from the crack weakly illuminated the clearing around it.
On the top of each withered tree, sitting cross-legged, rested a being.
Suddenly, one of them opened its eyes. It sat on the tree closest to the silver-leafed tree. Its appearance was vaguely human, although its skin was black like obsidian and its eyes were white circles without pupils.
"Any news about Shibai?" it asked in a neutral voice.
A few trees away, a slender creature, resembling a hairless monkey whose arms were so long they almost touched the branches of the tree it sat on, growled in evident annoyance:
"That bastard masters the laws of space too well. It's like trying to catch smoke with your hands... he slips away every time we corner him."
The monkey waved one of its long hands, letting out a snap that sounded like a crack breaking in the distance.
It looked up toward the Sacred Tree.
"But that's exactly what makes him valuable."
Silence returned, but its voice broke it again, this time deeper.
"We... the Primordials, the firstborn of the Sacred Tree. We were the guardians and feeders of its will. Our race, the world-devouring trees, was created for a single purpose: to devour the vital energy and genetic material of worlds to form a fruit. From those fruits are born the descendants of the tree... living entities, born to grow, evolve... and in the end, be sacrificed to be devoured by us once they achieve transcendence."
With a sigh of resignation, it continued explaining:
"We cannot act directly on the material plane. We can only consume what the plane offers us through our children."
The monkey narrowed its eyes.
"But Shibai broke that cycle. He found a seed of our species. Instead of planting it properly, he modified it. He found a way to alter its essence, and with an unholy ritual used his own clan as a catalyst to create a fruit adapted to his species... made for him to consume."
It clenched its teeth with contained fury.
"Since then, not a single new descendant has been born. We have gone tens of millennia without evolution. We are stuck."
It turned toward the Sacred Tree, whose crack emitted a low hum.
"But there is still hope."
The monkey smiled, showing thin needle-like fangs.
"Shibai. Himself. His body has dissolved, but his soul and energy have fused into a single force... and his laws, especially those of space, are unique. If we manage to capture him and deliver him to the Sacred Tree... his essence could be the key to the evolution of the Sacred Tree."
As the monkey continued its passionate speech, its voice echoed among the dead trees, filling the air with ancient tension.
But then, without warning, the vertical crack running along the trunk of the Sacred Tree glowed with an intense silver light. A subtle vibration ran through the entire forest.
The crack slowly expanded with a dry creak, revealing a huge ancient and wise eyeball, whose iris was filled with countless rotating runes and arcane symbols that changed constantly, as if watching beyond the present, past, and future.
A wave of pressure swept through the forest. The creatures sitting on the tree tops, regardless of their form or nature, stirred in unison. Some emitted guttural growls, others opened extra eyes on their foreheads. The energy in the air vibrated. The tension became almost unbearable.
However, before anyone moved, the obsidian-skinned man standing at the foot of the Sacred Tree raised his hand. In response, all beings calmed down, though their eyes remained fixed on the living tree.
A few minutes later, one of the countless branches of the Sacred Tree slowly descended from the canopy. It slid through the air like a celestial serpent until it touched the forehead of the obsidian man. At the point of contact, the silver light shone even more intensely, casting trembling shadows on the surrounding trees.
For a moment, everything fell silent.
Then, the branch slowly withdrew, and the great eye in the trunk began to close. The runes disappeared one by one until the crack was sealed completely, indicating that the Sacred Tree, the Tree of Time, had fallen asleep again… and this time, deeply.
The obsidian man kept his eyes closed a few more seconds. When he opened them, a wide and calm smile appeared on his face.
"The Tree has spoken," he announced, his voice echoing like an ancient reverberation. "Someone is rewriting the timeline of the central reality. Not creating branches... not generating alternate worlds... They are modifying the main line. Rewriting history itself without producing divergences."
A shiver ran through the Primordials. Disbelief, confusion, even fear crossed some of their faces.
"That's impossible," murmured a winged creature with feathers made of obsidian. "Not even the oldest beings in the universe can do such a thing without fracturing the space-time continuum."
"Correct," replied the obsidian man with a somber look. "Only one existence on this plane has been capable of manipulating the central line without creating bifurcations... and it is the Sacred Tree itself. Our father tree. The Tree of Time."
Silence thickened.
"The Tree ordered me to capture him," he added solemnly. "It said that sooner or later, that individual will come to this plane. And when he does, I must catch him personally. No matter the cost."
A creature with a deer's head and multiple mouths on its torso asked in a deep voice:
"Did it tell you when he will appear?"
The man shook his head.
"It tried to find out. Tried to decipher his identity and origin... but the Laws of Time could not reveal anything. That being is hidden even from the Tree. It's as if time itself hides him."
The Primordials' gazes turned somber. One who could hide from the Tree of Time... was a threat. And also, perhaps, a key for the Sacred Tree to break its shackles.
Silence fell once again over the Devouring Forest.
AN: For those who might think I made up this plot, let me explain that according to Boruto, Shibai truly ascended to a higher plane, abandoning his physical body, which ended up in the shinobi world in the future. I plan to make this higher plane the place where beings like Hashin (the god worshiped by Hidan), Amaterasu, Susanoo, and others exist. Also, I plan to add the Nano Machine world(manwha) to the same Naruto universe, as well as a standard immortal cultivation world( two or three chapters) and some worlds from magic and knights manhwa.