Sasuke recalled the principle behind Tsukuyomi: "The user drags the enemy into the world of Tsukuyomi, where time, space, and matter are all under the caster's absolute control."

He pondered, what if the "Eighteen Layers of Hell" were set as a series of eighteen distinct realms, and to break free from the illusion, one must dismantle each layer, one by one? Upon entering each level, the victim must either break the illusion immediately or endure the torment within that layer.

Each layer would last one full watch (approximately two hours). Once trapped in the "Eighteen Layers of Hell," the victim would either have to shatter the illusion or suffer punishment. After withstanding the torment for a full watch in the first layer, they would then be transferred to the next, continuing until all eighteen layers had been endured, only then could they escape.

Sasuke found some of the tortures insufficiently terrifying, so he decided to incorporate the ten most gruesome punishments from Chinese history to replace some of the existing levels.

The newly modified "Eighteen Layers of Hell" began with the first—The Hell of Tongue Extraction. Imps would pry open the victim's mouth, grip the tongue with iron tongs, and slowly tear it out—not in a single yank, but by pulling it long, inch by agonizing inch. Once torn, the tongue would regenerate, only to be torn out again, in an endless cycle.

The second—The Hell of Scissors: The victim’s ten fingers would be severed, and just as they regrew, they would be cut again, continuing without end.

The third—The Hell of Iron Trees: Blades sprouted from the iron trees, and the victim’s back would be pierced by the sharp edges, suspending them high in the air.

The fourth—The Hell of Skinning: Starting at the spine, the executioner would slice the back open, peeling the skin apart like butterfly wings, slowly stripping the flesh from the muscle.

The fifth—The Hell of Steaming: The victim would be placed in a steamer and boiled alive, only for a cold wind to blow through, restoring their body, so the torment could be repeated.

The sixth—The Hell of the Copper Pillar: Stripped bare, the victim would be forced to embrace a glowing red-hot copper pillar, their flesh seared by the unbearable heat.

The seventh—The Hell of Waist Severing: The victim would be sliced in two at the waist. With most vital organs located in the upper half, they would remain conscious, suffering for a long time before finally succumbing to death.

The eighth—The Hell of Dismemberment: Five horses would pull the victim’s limbs in different directions, tearing them into six pieces.

The ninth—The Hell of the Boiling Oil Cauldron: Stripped and plunged into a vat of boiling oil, the victim would be fried alive, endlessly tossed and turned in the searing liquid.

The tenth—The Hell of the Bull Pit: Cast into a pit, the victim would be trampled and gored by a herd of wild bulls.

The eleventh—The Hell of the Five Punishments: The victim would be beheaded, have their limbs chopped off, and their torso divided into three pieces.

The twelfth—The Hell of Lingchi: Two executioners would begin at the feet, slicing away a thousand pieces of flesh, one cut at a time, until the victim finally died.

The thirteenth—The Hell of Hanging: A bowstring would be tied around the victim’s neck, twisted tighter and tighter until they were strangled to death.

The fourteenth—The Hell of Castration: The victim’s genitals would be tied tightly with rope until the blood flow was cut off, causing necrosis. Then, with a swift slash, everything would be removed, and the wound sealed with ash.

The fifteenth—The Hell of Dissection: The kneecap would be sliced away, a cruel form of amputation.

The sixteenth—The Hell of the Volcano: The victim would be cast into a volcano, burned alive but never allowed to die.

The seventeenth—The Hell of the Grindstone: The victim would be ground into a bloody pulp, only to have their body reformed and the process repeated.

The eighteenth—The Hell of the Saw: Bound in a spread-eagle position between four posts, the victim would be sawed in half, starting from the groin and slowly working up to the head.

"This is too cruel... too inhumane..." Sasuke muttered as he stared at the latest version of the "Eighteen Layers of Hell" written on paper. He couldn’t help but shudder, while at the same time offering a silent tribute to the inventors of these tortures. How evil must someone be to conceive such horrors? Yet giving up was not an option for him. He would stop at nothing for power. Without immense strength, how could he possibly protect Uchiha Mikoto from the impending disaster two years from now?

"If I can master the 'Eighteen Layers of Hell,' it will surely surpass Itachi's 'Tsukuyomi,'" Sasuke thought, a surge of excitement propelling him to jump on his bed.

"Let’s not waste any time. I’ll start with the first level." He sat cross-legged on the bed, preparing to create his new genjutsu.

"Ah, I’m exhausted... Who would have thought I’d accomplish nothing after an entire night?" He stretched, noticing that dawn had already broken outside his window.

"If the first layer is this hard, I can’t imagine how long it will take to create all eighteen," Sasuke murmured in frustration, realizing the vast gap between thought and action.

"But I won’t give up. The difficulty only proves its potential!" he declared, standing before the window, resolute as the first rays of sunlight bathed his face.

--- One Month Later ---

"Ha... Ha ha ha..." Sasuke's laughter echoed through his room.

"Finally, a month of effort has paid off!" He restrained his laughter, though his face still radiated satisfaction. For the past month, aside from sending his clones for training, his true self had remained in his room, wholly focused on creating the first layer of the "Eighteen Layers of Hell"—the "Hell of Tongue Extraction."

"If not for my Sharingan, it would’ve taken even longer. With the boost from my eye’s power, the first layer has gained a new edge. It seems this technique will be inseparable from my Sharingan, much like 'Chidori' relies on the enhanced perception of the eye."

Sasuke thought to himself, "Now, let's see the true power of what I've created over the past month."

He cast the illusion of the "Hell of Tongue Extraction."

"What? It's only a C-rank genjutsu?"

Disappointment washed over him as he realized the illusion was graded merely as C-rank.

In truth, it wasn’t that the technique lacked strength; the space within the "Hell of Tongue Extraction" was too unstable, making it easy to break. Against Orochimaru, it might show A-rank effects, but against Itachi, it would be useless. No matter how powerful a technique, if it could be broken in an instant, it was worthless.

The instability lay in Sasuke’s current weakness; his Sharingan had only awakened one tomoe. Once he became a Jōnin or Kage-level ninja, with his Sharingan evolving to three tomoe or even the Mangekyō, this illusion would become as formidable as Itachi’s "Tsukuyomi." Only then would the "Eighteen Layers of Hell" reveal its true terror.