Originally, Sakura had been nothing more than an average earthling, her only unique trait being that she'd been cast into a cruel world where death was a daily occurrence; the result of some sort of cosmic power struggle.
Indeed, Sakura was no Shōnen protagonist. She was not pure of heart— unless one counted her single-minded, all-consuming appetite for gooning as a form of purity.
Indeed, her body, in its current incarnation, was a temple devoted to boundless lust, fuelled by gluttony for sweet things, fashioned by envy towards other women and tempered by laziness. To make matters worse, her misbegotten abilities had left her swollen with ill-deserved vainglory. She felt negative emotions like any normal person, such as fear, anger, sorrow and guilt.
…though it had to be said that a bit more shame would have done her some good.
And yet, for all her shortcomings, Sakura was not a bad person. Despite being little more than a living weapon in the shape of a woman, she did not take lives needlessly. She cared deeply for her friends and comrades, and she was a patriot who loved her village, even when it didn't deserve it.
However, it hadn't always been this way…
…
"Show me the darkness in your heart…" the leech whispered in Sakura's ear.
The light in Sakura's eyes grew dim as the Zero-Tails' tentacled arms slowly tightened around her body. A shadow crossed her heart as the leech-like chakra monster probed for cracks and vulnerabilities through which it might worm its way into her psyche.
"Such delectable guilt…"
Sakura's greatest regret was failing to tell Sasuke in time that she was not a true Uchiha.
Owing to Sasuke's fragility of mind at the time, Tsunade had initially counselled Sakura not to mention Nanashi to him. Yet, as the years slipped by, the prospect of telling him the truth had grown ever more remote. Preferring the status quo to the alternative, Sakura had continued to lead him on, offering him the false hope that he was not truly the last of his clan.
For Sakura's sake, Sasuke had relinquished the heart of an avenger and allowed his soul to fill with light, yet his hope for a warm future rested on the ugliest of lies.
"If only Sasuke knew the truth… I wonder what he would think?"
"I won't let him learn the truth…" Sakura replied, her eyes glazing over. "If he does…"
The Zero-Tails coiled more tightly around her and lowered its masked face to hers. How very curious, it thought. Though Sakura's heart was an open book, there remained portions it could not read: knowledge of the original timeline. Even with the System gone, its seal lingered stubbornly.
"Show me…"
A small gasp of pain escaped Sakura's lips as her eyes turned scarlet, three coal-black tomoe spinning into orbit around her dark pupils. They began rotating rapidly, their forms wavering and stretching…
"I won't let him leave the village," said Sakura dully. "Even if he hates me for it."
It is said that eyes are windows into the soul, yet among all eyeballs, those of the Uchiha clan are especially unique. The Sharingan reflects not only the soul of its bearer but also that of anyone who gazes into it, entwining them in a silent duet between yin and yang. But when the user's emotions reach an extreme pole, a miracle occurs: the eyes bring forth and manifest a power corresponding to their wielder's deepest longing.
Deep down, Sakura's heart wanted two things more than anything else: for Sasuke to never leave her side, and for him to notice her. And thus, from the day she had first obtained the Uchiha clan's breast chakra, two different Genjutsu powers had already begun germinating within her cursed pupils: Kotoamatsukami in her left eye, and Ame-no-Uzume-no-Mikoto in her right…
…
Sakura felt as though she were drowning.
She floated in the foetal position, suspended in darkness, her arms drawn tightly around her knees. Hushed voices whispered in her ears as the currents of an endless sea of despair rocked her to and fro.
In her mind's eye, Lady Tsunade's fragile, withered form lay curled on the ground before her, lifeless. Doctor Shinnō had tried his best, yet he too lay dead, his neck bent at an unnatural angle. Sasuke walked away from her in disgust, and no matter how she strained her throat, not a single cry would form to draw his attention. The villagers pointed their fingers at her, sharp with accusation.
"…!" Sakura cried.
And yet…
Despite the Zero-Tails' best efforts, it couldn't force her subconscious to imagine the impossible. Standing tall in the middle of the icy river engulfing her, two smiling figures braved the current in Sakura's mind, wreathed in light amidst the gloomy waters.
"Naruto…" Sakura murmured weakly, extending her hand towards them. "Karin…"
Warmth blossomed in Sakura's chest, pushing back the darkness. With nothing left for it to cling to, the Zero-Tails slowly withdrew from her body.
…
Sakura's eyes flew open. It seemed like she had somehow found herself in a prison cell, dimly lit by green, fluorescent lights. Unconscious men and women lay strewn across the floor in every direction. Without even trying, she had found the missing villagers from Amaru's hometown!
With some effort, Sakura pushed herself to her feet and shuffled over to the metal bars and peered outside. Her jail appeared to be only one of many such cells, and what's more, there was something about this environment that sapped her chakra as quickly as she could mould it…
"Hrnnngh!"
Sakura gripped two bars and tried to prise them apart, but the burning sensation spreading across her palms quickly told her that touching them was a very bad idea ("ouch!"). She backed away from the bars and examined her fellow prisoners more closely. Their bodies seemed to be emanating black wisps of chakra.
"Dark chakra born from negative emotions, eh?" Sakura muttered to herself, remembering Yomi and the demon Mōryō. "In that case… Shion's holy priestess magic ought to do the trick."
While sage power could be combined with chakra to produce Senjutsu, sage magic by itself didn't require any chakra, only a special bloodline or the ability to sense nature energy with one's spiritual energy. Convenient when kneading chakra was impossible!
One by one, Sakura called to mind the hand seals that the Land of Demon's miko had taught her, and she performed the Breaking of the Seal Spell.
Min! Shin! Gan! Reppyo! Shōzen! Mika! Dan! Raku! Shō!
"Release!"
A pink glow radiated from Sakura's body, ridding the Zero-Tails' thralls of the monster's pernicious influence. The prison bars shattered, and the purple glow of the jutsu formulae etched into them flickered and sputtered before fading to nothingness.