Mo Yu quickly asked the system:
"Could it be… if his ability is Kotoamatsukami, I'll end up under his control?"
The system replied calmly:
"No. The system is bound to the host's will. Any technique that interferes with willpower will have no effect."
Mo Yu let out a breath of relief. That was basically like having a built-in "passive skill."
At that moment, Uchiha Fuhai's Sharingan finished its evolution. The three tomoe vanished, replaced by a pair of windmill-like patterns.
This was the most common Mangekyō Sharingan type. If Mo Yu guessed correctly, then the abilities of these two eyes should be—
"Tsukuyomi!!"
Fuhai's gaze locked on him with a roar.
Mo Yu's vision blurred. The forest vanished.
He was now in a space of absolute darkness. Overhead hung a massive blood-red eye, radiating a suffocating aura.
Mo Yu himself was crucified on a cross, heavy chains binding his body.
This wasn't like the illusions from earlier. The sensations here felt utterly real, with almost no flaws.
"The Tsukuyomi space."
Mo Yu understood instantly.
He tried activating his Sharingan, but it did nothing.
Against the Mangekyō, his two-tomoe Sharingan was hopelessly outclassed. The difference in level meant it was naturally suppressed.
Before him stood Uchiha Fuhai.
Mo Yu was just about to speak when he noticed Fuhai's face frozen in shock, as if he had seen a ghost.
"You… you also have the Sharingan?!"
Mo Yu realized at once what had happened.
This was Tsukuyomi space—everything here was woven from spiritual power, including his own form.
Since Sharingan drew partly on chakra but also on spirit, his true eyes were revealed here. No contact lenses could conceal them.
No wonder Fuhai was so stunned.
Mo Yu smiled faintly. "Take a guess."
"Could it be… you're a lost orphan of the Uchiha clan?"
Fuhai muttered to himself.
In the days before Konoha was founded, the shinobi world had been in chaos, with clans constantly at war. Some bloodline descendants could be scattered into obscurity.
"Heh."
Mo Yu chuckled but didn't confirm or deny.
"Hmph. Won't talk? Fine. I'll dig your secret out piece by piece. But first—allow me to show you the terror of the strongest Sharingan illusion!"
Hatred filled Fuhai's eyes.
Even if he believed Mo Yu might be a lost clansman, that didn't mean he intended to spare him.
"I'm not very well-read, but isn't the strongest Sharingan illusion supposed to be Kotoamatsukami?"
Mo Yu teased.
Fuhai's face went stiff. The slap of truth was uncomfortable.
Mo Yu was right: the true number-one illusion of the Sharingan was indeed Kotoamatsukami.
But awakenings of Kotoamatsukami in Mangekyō history were vanishingly rare. Its activation conditions were so extreme that it couldn't be treated as an ordinary jutsu. Thus, within the Uchiha, Tsukuyomi was usually regarded as the supreme genjutsu.
"You really do know a lot. All the more reason I want to uncover your secrets!"
Fuhai sneered.
He waved his hand, and an invisible whip lashed across Mo Yu's body.
Crack!
Mo Yu's face went pale, his body wavering as if about to dissolve.
The whip was pure spiritual force, a weapon to strike at the mind.
Fuhai was startled that Mo Yu didn't scream. Scowling, he shouted: "Fine, let's see how long you can endure!"
Whip after whip fell.
Mo Yu gritted his teeth, never letting a cry escape.
His endurance was thanks to the earlier training within the "Hell of Blades and Fire" illusion. Compared to that torment, Fuhai's Tsukuyomi felt almost childish.
Though Mo Yu's eyes were only two-tomoe, in terms of sheer spiritual strength, he wasn't necessarily weaker than Fuhai.
Besides, Mo Yu knew something else—though it seemed like he was the one taking blows, in truth, Fuhai was suffering too.
Force and counterforce: when Fuhai lashed with spirit, the recoil also damaged his own psyche.
Tsukuyomi was essentially a "mutually harmful" technique—hurt the enemy by a thousand, harm oneself by eight hundred.
Victory came down to whose will and spirit were stronger.
In the original story, when Itachi used Tsukuyomi on Kakashi, he tortured him in that world for days.
And yet, though Kakashi spent a month in a coma afterward, Itachi didn't walk away unscathed either—the Mangekyō's toll quickened, his spirit exhausted, unable to use Tsukuyomi again for some time.
As Mo Yu "suffered," inspiration struck.
Since he couldn't escape for now… why not use this chance to temper his spirit? It might even help push his Sharingan toward the three-tomoe stage.
He had calculated before: his Sharingan's growth was too rapid, leaving it stuck at a bottleneck. Without a miracle, three to five years might pass before he reached three tomoe.
And now—here was the miracle.
What better way to polish one's spirit than within Tsukuyomi itself? Best of all…
It was completely free!!!
For a miser like him, nothing sounded sweeter than "free."
The thought even lifted his mood.
"Come then—let the storm rage harder!"
Mo Yu endured the lashes, converting the pain into strength, forging both spirit and ocular power.
It was true pain—but also true joy.
One day. Two days. Three days…
Mo Yu's spiritual body grew thinner and thinner, nearly transparent, looking as though it could collapse at any time.
Yet the will that remained was resilient beyond measure—like grass sprouting from stone, battered by storm after storm, but never bowing.
Then he noticed something even more shocking: with each lash of Fuhai's spiritual whip, fragments of his power seeped into Mo Yu's eyes—and Mo Yu's Sharingan absorbed them.
Absorbing them, he immediately felt the bottleneck loosen, as if a path forward had opened.
Ecstasy welled in Mo Yu's heart. He hadn't expected such a benefit.
Perhaps in all history, no one else had ever used Tsukuyomi as a way to refine their Sharingan.
He couldn't help the smirk tugging at his lips, though he quickly masked it with feigned agony—encouraging Fuhai to lash even harder, while secretly siphoning more power to strengthen his eyes.
Three more days passed…
Mo Yu's spiritual body had regained solidity—now even sturdier than before, as though fortified with nourishing elixirs.
Fuhai, on the other hand, looked utterly drained.
His face was ashen, his body weak and trembling.
At last, he could no longer lift his hand.
Staring at Mo Yu in horror, his fingers quivered as he pointed.
"You—!"