At a time like this...
How could Black Zetsu possibly let Emiya Shigen sit quietly and think things over?
Black Zetsu had lived for more than a thousand years—he knew all too well what could happen when someone was left alone to process shocking revelations. People tended to spiral into overthinking, and worse, they often concocted wild, world-ending conspiracy theories in their minds.
And the most dangerous part?
Black Zetsu actually did have a world-ending conspiracy in the works.
He couldn't risk Shigen figuring that out. Especially because Shigen, born in the ancient era, already knew far too much about the old world. If he was allowed to piece things together on his own, he might even deduce the real truth behind Kaguya's disappearance.
No, that couldn't happen.
Black Zetsu needed to act fast.
He had to seize this moment to plant his version of the story in Shigen's mind—a carefully crafted tale that would make Shigen accept his words as truth and leave him fully indoctrinated.
"I need you to hear me out."
The words felt oddly familiar to Black Zetsu.
Because Shigen had just said the same thing to him.
How ironic.
Black Zetsu couldn't help but feel like this was some kind of fated cycle, a karmic loop.
Still, there was no other choice. He had to imitate Shigen's approach and tell a story—one that was heavily edited to suit his agenda.
"In our time..."
"You've heard the story of the Divine Tree, haven't you?"
Black Zetsu's voice was low and somber, weaving an ancient tale.
"In the ancient era, the Divine Tree appeared in this world. It became a symbol of faith for humanity. And alongside it descended Kaguya—known to humans as the Rabbit Goddess, Otsutsuki Kaguya."
"But..."
"There's something you don't know."
Black Zetsu's eyes gleamed as he continued, his tone darkening.
"Even in that ancient era... humans were locked in endless conflict."
Black Zetsu crafted his tale carefully. He knew that Shigen admired people who sought to relieve suffering, so he painted Kaguya as a benevolent deity who had come to bring peace.
"In those days, humanity was plagued by suffering and war. People prayed to Kaguya, begging her to end the bloodshed."
"And she heard their prayers."
"She used the power of the Divine Tree to stop the wars and bring peace to the world."
"But..."
Black Zetsu's tone grew heavier.
"That wasn't the end."
"Even though Kaguya possessed godlike power... even though her strength was unparalleled, she eventually encountered a problem she couldn't solve."
Black Zetsu paused, intentionally drawing Shigen in.
He knew how to manipulate people—he had been doing it for centuries. Make them feel connected. Relatable.
"Think about it, Shigen..."
"Surely, you can guess what that problem was."
Shigen frowned, deep in thought.
"Too many people?"
"Exactly."
Black Zetsu nodded quickly, not giving Shigen time to finish his thoughts.
"Kaguya wanted to share her power—to give her chakra to those with noble hearts, like you. She believed that if good people had power, they could help relieve the suffering of the world."
"Me?"
Shigen shook his head modestly.
"No, no... I'm no saint. I was merely a lucky man blessed by the remnants of the Divine Tree. I just didn't want to waste that power, so I sought to help others—like the Rabbit Goddess did."
"Don't be so humble."
Black Zetsu insisted, refusing to let Shigen downplay his importance.
"I've walked this world for over a thousand years... and I've never seen anyone like you."
"In this entire world..."
"People with hearts like yours are far too rare."
Black Zetsu sighed, using the moment to push his story further.
"But Kaguya knew that chakra's influence was too powerful. She understood that it couldn't be given freely. If it fell into the wrong hands, it would only cause more suffering."
"Of course."
Shigen nodded solemnly.
"Such a powerful force must be given out cautiously."
"Exactly."
Black Zetsu sighed again, as if lamenting the tragedy of it all.
"That's why her plan wasn't going smoothly."
"But for Kaguya, it wasn't a big issue. She had endless time. Her lifespan was far longer than any mortal's. She believed she could wait—patiently seeking out those truly worthy of receiving chakra."
"She was right to be careful."
Shigen agreed wholeheartedly.
"If chakra were handed out recklessly, it would inevitably bring disaster."
"Yes..."
Black Zetsu's voice lowered ominously.
"But Kaguya's two sons didn't share her cautious approach."
"Wait—two sons?"
Shigen's expression changed.
This version of the story was different from what he knew.
"Yes."
Black Zetsu's voice darkened.
"In addition to the Sage of Six Paths, Otsutsuki Hagoromo, Kaguya had another son—Otsutsuki Hamura."
"Both of them were born with chakra. And because they had always known it, they didn't see it as something rare or sacred."
"They believed their mother was wrong to withhold it from humanity. They thought she should give chakra to everyone, and let people decide their own fates."
Black Zetsu carefully framed his words to plant seeds of doubt about Hagoromo's wisdom, without outright condemning him.
"Their ideas were naive."
"They believed humanity could handle such power. But Kaguya... she foresaw what we see today."
"She knew that if chakra was given to humanity, it would become a tool for war and suffering."
Shigen's expression grew darker.
"...They were reckless."
"Yes."
Black Zetsu nodded.
"Exactly."
"And now we see the consequences of their actions."
"But..."
Black Zetsu continued his tale.
"The sons couldn't accept their mother's vision."
"They misunderstood her wisdom. And because Kaguya had always doted on them, she failed to command their respect."
"So..."
"They rebelled."
Shigen's eyes narrowed.
"They... fought her?"
"Yes."
Black Zetsu's voice dripped with bitterness.
"They used the very chakra she gave them to start a war against her. A war so destructive, it nearly ended the world."
Shigen's face paled.
"The Great Catastrophe..."
"Yes."
Black Zetsu nodded grimly.
"That disaster wasn't caused by external forces. It was the result of two sons rebelling against their mother."
"Their battle devastated the land, killing countless innocents caught in the crossfire."
"Kaguya didn't want to fight her children. But when she saw the destruction they wrought... she had no choice."
"In the end..."
"The war ended."
"Kaguya... was sealed away by her own sons."
Black Zetsu paused.
He needed to make sure Shigen understood.
"They feared her."
"They feared that, after their deaths, she would reclaim all the chakra they had given to humanity."
"And so..."
"They chose to imprison her."
"...And the Rabbit Goddess disappeared from the world."