As soon as he set foot in this world, Noah knew he had already been detected. The alley where he appeared was deserted, but the atmosphere was heavy with an invisible presence. Someone—or something—was watching him.
A few meters away, a girl playing on the sidewalk suddenly froze. She lifted her head with unnatural movements. Her eyes were no longer hers.
A faint smile formed on her face, but her pupils turned completely cold, devoid of humanity.
"What does a foreigner like you want in this world?"
Noah remained unfazed. He had anticipated that his arrival would not go unnoticed.
"Knowledge," he answered calmly. "I want to understand how this world works. Its laws, its alchemy. Nothing more."
He slowly raised his hand. Floating above his palm, a small sphere materialized. Inside, data, formulas, and notes swirled—chemical knowledge gathered by one of his clones during his time at university.
"In exchange, I offer this knowledge. I can give you more, if you leave me alone while I'm here."
The entity speaking through the girl fell silent. Finally, it replied in a neutral, almost indifferent tone:
"I like this deal. It aligns with the law of equivalent exchange. But there will be conditions."
Without warning, the girl's left eye began to mutate. It opened wider than normal, grotesquely swelling. Then, two reddish arms sprouted from the socket. The eyeball emerged from her skull, trailing optical nerves that morphed into thin, membranous wings, like those of a bat. It hovered in the air for a few seconds, then gently descended and perched on Noah's shoulder.
"First: do not interfere in this world's current conflicts.
Second: limit your contact with its inhabitants.
And third: I will always be watching you."
Noah stared at the strange eye without a word, then turned his gaze back to the girl. Within seconds, her eye regenerated as if nothing had happened. She blinked, confused, and ran off in search of her mother.
The eye on his shoulder settled lightly. Noah scanned his surroundings, then nodded.
"Understood," he said, and walked away, ready to begin his exploration.
But at that moment, unnoticed by Truth, a figure that had remained still a few steps behind Noah began to move. Once Noah was out of sight, the figure turned in the opposite direction, merging with the shadows.
Over the next few days, Noah traveled through Amestris disguised as a simple traveler. He sought out alchemists to exchange knowledge, analyzed transmutation circles, and collected all sorts of data. He remained true to his word: he didn't interfere, didn't disturb. Even Truth began to think the stranger was truly a believer in the law of equivalent exchange.
But everything changed on the seventh day.
An eclipse covered the sky. A shroud of darkness fell upon Amestris. Noah looked up and smiled, as if he had foreseen everything.
"Then it should have already begun."
He kept walking as if nothing was happening. The eye on his shoulder rotated slightly, focusing on him with an expression that, despite having no face, seemed suspicious.
In the depths of Central City, a massive transmutation circle carved into the rock began to glow. At its center, Father watched in silence, surrounded by five unmoving figures: Edward Elric, Alphonse Elric, Roy Mustang, Izumi Curtis, and Van Hohenheim. The sacrifices. The key pieces of his ritual.
On the surface, soldiers and alchemists battled the Homunculi, unaware of what was coming. And then, everything happened at once.
The ground shook. The light from the underground circle spread, piercing through rock, concrete, and steel, rising like a wave to cover the entire country.
In mere seconds, all of Amestris fell.
Soldiers, civilians, children, the elderly. Their souls were ripped from their bodies and absorbed into the alchemical matrix, concentrated into a single point.
Noah, walking along an empty street, suddenly stopped. His body trembled slightly before collapsing. The eye floating above his shoulder curved slightly, as if laughing.
A translucent form rose from Noah's body: his soul. A dark tendril emerged from the ground, fast as a snake, aiming to seize it. But the eye acted first: it fired a beam of energy that destroyed the tendril, then opened its center and absorbed both the soul and the body.
After that, a small illusory door appeared in the air. The eye passed through it and vanished without a trace.
Meanwhile, the ritual continued.
The sky tore open, and a giant eye emerged from the clouds, gazing down at the city. A Gate of Truth opened above the national transmutation circle, and from it emerged a humanoid colossus, pitch-black, with a single red eye on its forehead.
Father, ecstatic, raised his arms to the sky.
"Now I will have God within me!"
He plunged both hands into the Gate and pulled. The eye of God was torn out and absorbed. The gate slammed shut with force.
When Father returned to the physical realm, he was no longer the same.
His body, though human in appearance, radiated an unnatural aura.
In the chamber, Hohenheim stepped forward. He had waited years for this moment. While Father gloated, Hohenheim activated his countermeasure: a secret counter-circuit woven patiently, using fragments of his own soul and that of the former citizens of Xerxes.
From all regions of the country, a contrary energy emerged. The stolen souls began returning to their bodies. Father, stunned, felt his power crumbling.
"What have you done?!" he roared, turning to Hohenheim.
"The souls were never yours," the alchemist replied calmly.
Then, amid the chaos, as Father let his guard down for a second while focused on Hohenheim, a hand emerged from nowhere. It pierced through his alchemical shield like paper and landed on his head.
Simultaneously, in another plane separated from reality, Truth finished breaking all the seals and barriers of Noah's supposed soul and eagerly dove into his memories—only to find a single one.
In that memory, a man smirked mockingly at him, flipped him the middle finger, and then shattered like glass, leaving Truth stunned.
In reality, the true Noah had always been hidden under an invisibility cloak, and the one interacting with Truth from the start was merely the product of two new techniques developed by Noah.
The first was the Soul Clone. Using his knowledge of Horcruxes along with various spells and jutsu, he developed a technique that allowed him to create a clone of his soul using spiritual energy.
As for the body, it belonged to a random dark wizard whose soul Noah had eradicated before making the soul clone possess the body. Though it cost him all the spiritual energy of his soul and downgraded him from maximum rank 0 to the starting rank, it was well worth it, as this soul clone successfully deceived Truth.
Since the clone could self-destruct at will and the body was of no importance to him, Noah had no concern about Truth capturing it.
Back in Central City, Noah used a precise electric discharge to disable Father's brain, causing his body to collapse.
Before the being known as God could flee from the now unconscious body, a net of chakra-made chains bound it within Father's body, preventing its escape.
Calmly and without haste, Noah grabbed the inert body and stepped through a spatial vortex, vanishing into the void, while behind him, Truth roared, deceived and furious.
---
Back in his laboratory, Noah began analyzing his spoils. He placed both hands on the unconscious Father's head.
The cocoon of chakra chains inside Father reacted to his chakra and was expelled from the body. Noah removed his hands, and now there was a ball made of chains, from which dark tendrils protruded.
Through the chains, he began to study this eye. Before entering the world of Fullmetal Alchemist, Noah theorized that Truth must be something like a world will or the embodiment of the world itself. As such, this eye—part of it—contained some of its essence.
Noah noticed that the eye had a faint consciousness. Though weak, it was there, and he would have to find a way to erase it in the future.
From the moment he set foot in that world, Noah's goal had always been this eye. This eye was the crystallization of the fundamental law of the Fullmetal Alchemist world: the law of transmutation.
Focusing, he placed the eye on a wide stone platform and began drawing a large circle with chakra, dividing it into eight sections. In each, he placed the classic trigrams—long and short lines representing different elements. In the center, he drew the Uzumaki clan's spiral symbol.
Then he took a deep breath and sat at the center of the seal. He placed the eye wrapped in chains before him and pressed his right palm over the central symbol.
"Sealing, commence."
He released a wave of chakra that fed the seal. The lines glowed and began to rotate slowly. A symbol similar to the one on the ground appeared on Noah's forehead and began to pulse with energy.
The chains containing the eye cracked and shattered into fragments. The eye shot upward, floated briefly above the seal, then was pulled by the energy flowing from the center into Noah's forehead.
Noah felt pressure at his forehead. It was as if the eye was resisting, but it lacked the strength. The seal fully activated, and a chakra surge pushed it into his body.
The eye fused with him, and on his forehead, the seal's symbol faded, replaced by a vertical crack.
Noah opened his eyes, and simultaneously, the vertical crack opened, revealing a gray eye with a ripple pattern in the iris.
He raised his hand, and an electric current ran through the floor before a stone staff rose into his hand.
Noah grasped it, and the staff transformed—first into a sword, then a spear, continuing to change until Noah finished testing his new power.
The staff then turned to dust, which floated back into the hole in the ground from which it had formed, fusing again with the stone.
A slight smile curved Noah's lips as he turned his attention to the homunculus, Father. Approaching him, he began extracting all the information he held on alchemy.
Being able to manipulate the law of transmutation freely and use alchemy naturally didn't mean he could use it with versatility.
Father's memories saved him decades of study and revealed many different ways to use transmutation.
Now that the homunculus was of no more use, Noah reduced him to ashes using Fiendfyre.