Following Saber's explanation, Tohsaka Rin basically understood the cause of the current situation.
When the Holy Grail began to overflow with black mud from the hole to the outside world, Jalter's heart was damaged, temporarily preventing her from unleashing her vengeance flames to burn the curse. This led to the helpless Jalter, and the caught-off-guard Saber and Kiritsugu Emiya, being engulfed by the suddenly erupting cursed black mud.
Under the erosion of all the worlds evils, only Jalter, who herself was a manifestation of the principles of curse and revenge, and possessed the Avenger class, could remain unharmed. In fact, one could say she was as free as a fish in water within it.
"At that moment, I was engulfed by the curse. All the regrets and sorrows of my past were magnified infinitely. I saw everyone from the Knights of the Round Table, each with faces full of unfulfilled regret, angrily denouncing me with their resentment. I almost collapsed again, falling into the abyss of darkness..."
But fortunately, Lancelot's atonement and redemption, his peacefulness in release, and his words supported Saber's spirit, preventing her from falling.
"The king protected the country, but the country did not protect the king. If anyone is truly at fault, it must be us, the Knights of the Round Table, who failed to protect the king! The king was just an ordinary young girl; this is something every one of us knew perfectly well."
Lancelot's words supported Saber's heart. With this, she firmly believed that the Knights of the Round Table did not resent her; they supported her until the very last moment. Faced with such an unyielding Saber, even all the worlds evils were helpless and unable to corrupt her.
"From the very beginning, I noticed a sneaky, rat-like fellow hidden in that black mud. As an Avenger, I should have been able to control those cursed black mud, but that fellow kept interfering with me. However, in front of me, another Avenger, he couldn't use those curses to attack me, so we had to rely on our own strength. So, I singled him out and killed him."
Tohsaka Rin knew that Jalter was talking about Angra Mainyu, the anti-hero who bore all the worlds evils. It was he who polluted the greater grail during the Third Holy Grail War, possessing the ability to manipulate the black mud of all the worlds evils, while his own power was the weakest, only at the level of a slightly more powerful ordinary person.
Because Angra Mainyu was completely killed by Jalter, another Avenger, all the worlds evils needed to find a spokesperson before being completely controlled by Jalter, so it sought out Saber, who was submerged in the black mud. But Saber's spirit consistently refused to break or surrender.
Since the negative shadows could not overcome the light, then perhaps the intention was to simply bring them forth.
Perhaps with this idea, all the worlds evils chose to completely strip away all the negative emotions hidden in Saber's heart—past regrets, vexations, resentments—from Saber's soul level. It then endowed this past shadow of Saber with a real body and soul, using pure, primordial sinful desire in the form of black mud. And just as extreme light represents extreme darkness, the Excalibur, a holy sword of the stars intimately connected to Saber's soul, also had its previously non-existent inverted shadow aspect stripped away by all the worlds evils and bestowed upon the newly created Black Saber.
"Pride, wrath, envy, greed, gluttony, sloth, and lust. These are the seven deadly sins, defined as the primal desires of humanity. What is called all the worlds evils is precisely the aggregate of all human desires. These things, when stirred together, are undoubtedly the greatest curse upon the world. But perhaps even that black mud itself never imagined that when all primal desires are gathered and compressed into one, the greatest sin, which should be the most unforgivable and utterly wicked, would be..."
"To live..."
When Jalter said this, the seemingly pure Black Saber spoke softly, her words instantly creating a stark contrast with the ruthless, iron-blooded king of knights from the original work/canon, which made Tohsaka Rin's nose bleed!
The seven deadly sins are the primal desires that drive biological action. However, no matter which one, ultimately, the initial desire for all of it boils down to "to live"—not wanting to die, to survive. This is the greatest and most primal desire of all living beings. The Star Devouring Demonic Sword - Emperor's Slash was born from this desire, the wish to not be annihilated and to continue life, a sword that saves people by destroying stars.
For the world, to live is humanity's greatest sin!
"And so it is. All sins gathered into one, yet the purest soul was born from it. It's an affirmation of the theory that things turn into their opposite when they reach an extreme. And that hole has already sealed itself, just as you, Master, said. So all the black mud that stopped flowing was absorbed by her to form her body. Then I picked her up and gave her to you, Master, as compensation for failing to protect the Holy Grail you wanted."
Jalter concluded. Tohsaka Rin, wiping her nosebleed with her back turned, asked again:
"Then what's the deal with Saber still being here? Without being eroded and incarnated by the black mud of all the worlds evils, as a Heroic Spirit summoned by the Holy Grail, shouldn't she return to the Hall of Heroes after the Holy Grail is destroyed...?"
"My ability to remain is entirely because of this child."
Saber's gaze fell upon the new life beside her, newly born from her own negative shadow.
"This child was born from my shadow, and my existence is the light that casts the shadow. So, after she gained a true body, I was forcibly retained in the present world as her light. Now, she and I are in a symbiotic relationship where we thrive or perish together. Like shadow and light, we confront each other and also prove each other's existence. Only when this child meets her end can I return to the Hall of Heroes... No, my obsession and wishes have already been fulfilled, and my contract with alaya has ended. If I return, I should go back to avalon."
"Then don't go back!"
Tohsaka Rin raised her hand and declared loudly:
"I will provide you with magical energy and true bodies! I can even complete your incomplete soul, Saber. Revive in this era, Saber!"
Saber paused at Tohsaka Rin's suggestion, then smiled and replied:
"I am deeply grateful, Tohsaka Rin. Just as Sir Lancelot said, meeting you truly is wonderful."
Jalter casually tilted her head and shrugged, saying:
"I don't mind. This Little Knight King doesn't seem to be a nuisance either. As long as Master is happy, and besides..."
Jalter suddenly, with lightning speed, pressed the Black Saber's small head into her magnificent 38E bosom!
"I'm quite fond of this child! Ha ha ha ha..."
"Wuwuwu..."
"Hey! Let her go, you'll smother her!"
"What's with that? Just now you looked disgusted, and now you're worried about her."
"This is different! Although she was born from shadow and defilement, she is the purest life! I will no longer look at others with prejudice. I will absolutely not repeat the same mistake..."
Rin couldn't help but smile, watching the three identical yet distinctly different faces, which had unconsciously gathered together, chattering and bickering.
Although the process was arduous, and the cost was painful, the ending was perfect, wasn't it? She protected her family, fulfilled her wish, and reaped both expected and unexpected rewards.
Wasn't the ultimate outcome of this Holy Grail War Tohsaka Rin's victory?
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