I have to say, Black Zetsu was a bit good at telling stories.
In its telling, Kaguya was transformed into a compassionate Rabbit Goddess, a victim harmed by those close to her. Even though her fate was so tragic, the great Kaguya still chose to prioritize the greater good. This story truly depicted the image of the Rabbit Goddess that humans wanted to believe in, especially for someone like Emiya Shirou who had always believed in the God Tree and Kaguya.
Shirou was a bit dazed. Is this the ninja world? Is this the proper ninja world?
If the storyteller wasn't Black Zetsu, he would have almost believed this tragic story. Logically, there was only one small flaw.
Because that one flaw was Black Zetsu itself.
In the ancient era, Black Zetsu always wanted to take revenge on the Sage of Six Paths. A mother who was soft-hearted and doted on her sons, even actively retreating during a world-destroying conflict... the will she left behind actually wanted to take revenge on her own son? Obviously, Black Zetsu didn't quite understand human emotions. As a kind person, Shirou would definitely take the initiative to help it patch up this flaw, which also greatly lessened his original guilt towards it.
"Truly," Shirou sighed at length, "a revered god. I can hardly imagine. Such a great god, clearly walking on the right path, yet betrayed and sealed by her beloved child. How much pain must be suppressed in her heart."
Black Zetsu's face suddenly froze. It didn't expect its story to be so effective! Shirou's reverence for Kaguya was growing higher and higher.
This guy even thought of Kaguya's pain when she was sealed! Although Kaguya felt more than just pain—there was also resentment and anger—Shirou's words immediately gave Black Zetsu a new idea. It immediately found an origin for its own existence.
"Yes. This pain is unbearable. Even the Rabbit Goddess couldn't bear it. This pain is also the reason for my birth." Its voice slowly grew gloomy. "That great mother was unwilling to hate her own son even before she was sealed. Kaguya separated her pain from her body, and thus I was born."
It seemed to have some self-pity as it continued, "So I have been hiding. Because I am the will of pain born from Mom, I dared not speak my true identity."
Shirou looked at Black Zetsu as if in a daze. "Black Zetsu..." A sense of compassion seemed to develop in him. At this moment, he seemed to have completely accepted Black Zetsu's identity and forgiven its past deception, and even felt some sympathy. "You are the will of the Rabbit Goddess. This should be something to be proud of."
He comforted it, even feeling a bit sentimental. "Gods are always saving the suffering world. Someone should come to save the gods' suffering. As the will of pain left behind by the Rabbit Goddess, you must also be protesting her fate."
"Lord Wei Yuan..." Black Zetsu was a bit moved. From today onwards, Shirou was its truly, perfectly controlled pawn.
No... I shouldn't have this thought... I should say... he is now my true companion in reviving Kaguya.
Although it felt that one day after Shirou revived Kaguya, when he truly saw her true face, he would probably become furious. However, to prevent that, Black Zetsu did not plan to let him see the revival. Because he was the sacrificial vessel it planned to use.
After all, only Shirou was the pawn it trusted the most. As for Madara Uchiha... it had completely forgotten about this still-useless pawn.
Black Zetsu fantasized about its future success. When it one day pierced Shirou's heart to revive Kaguya, should it have a triumphant expression? Or a sad, reluctant one? No, let's have both. It could be sadly explaining its helplessness while triumphantly revealing its deceptions.
This state seems a bit schizophrenic.
Although it felt a bit sorry for betraying his trust, it believed it was originally Kaguya's will. Yes, at that time, it would just say a few more words. Praise him a bit, talk about how much it liked him as a pawn. Before he died, it should let him know the truth. This could be considered worthy of their years of friendship.
While secretly making its plans, it even felt a bit of guilt, and its attitude towards Shirou subconsciously became more enthusiastic and close.
"Wei Yuan..."
Hearing the address, Shirou's mood became a bit subtle.
This fellow, Black Zetsu... does it think because it's Kaguya's will, its status has been elevated, and it's not even willing to call me Lord Wei Yuan anymore? The name Wei Yuan is for true friends to call! The kind of friends who can truly entrust their last wishes to each other!
I proactively let the slug call me that for convenience, and that little fool insisted on adding 'Lord'. This fellow... calling me Lord Wei Yuan was one thing, but now it won't even add an honorific. Does it really think being Kaguya's will allows it to look down on me?
Although I am a broad-minded person and don't intend to argue over such small matters, its behavior is a bit arrogant. To rise to power so quickly... it hasn't even risen yet! It's already putting on the airs of a god's will! Has this guy forgotten what's important! Right now, it still needs something from me!
"Wei Yuan," Black Zetsu really liked this intimate form of address. It believed their relationship had become closer, that Shirou had completely accepted its identity and forgiven it.
The time had come to talk about serious business. "It's not easy to revive Kaguya. Back then, when Mom was sealed, it was relatively easy. But her chakra has gradually dissipated over the millennium." It paused, then fabricated another line. "Now Mom has only left behind her thoughts, still protecting the world she once loved so deeply."
"How great," Shirou couldn't help but exclaim, then as if realizing something, he frowned. "If Lord Kaguya only has a remnant of her thoughts left, this is a realm of gods I have never touched. I might need a not-so-short period of time to try and explore and research it, but I'm worried I might not be able to do it."
Black Zetsu smiled. It didn't mind Shirou's powerlessness. It was satisfied with his attitude, even blooming with joy because his words brought back that familiar feeling!
As expected of Emiya Shirou! As expected of my favorite pawn!
When encountering a problem, he subconsciously looked for a solution. But this time, he definitely couldn't do it. Because the method of reviving Kaguya was something he couldn't imagine.
"I think... hmm?" Shirou was about to continue, to see what other tricks this fellow could come up with, when he sensed someone rapidly approaching.
Black Zetsu also sensed it and was a bit annoyed at being interrupted. "Someone's coming! Wait..." It sensed the visitor with some surprise, seeming to not believe their identity. "Why would he come here?"