The Sage of Six Paths was, if nothing else, sincere. He'd even gone through the trouble of sending Hashirama back from the brink just to deliver an apology. In the Sage's eyes, Shirou's status and character demanded that level of respect.
Shirou's gambit was a plea for him to save Hashirama, a plea he had to refuse for the sake of the world's safety. Thus, the apology.
"The Sage told me," Hashirama relayed, completely buying the explanation, "that this world faces a crisis more terrifying than Madara, and that he must be ready for it. He can't descend into the living world himself, but to apologize to you, Lord Emiya, he let me stay for just a moment."
"So..." Tobirama's face contorted into an ugly mask of frustration. "The Sage of Six Paths really exists. And we are truly insignificant to him. If it weren't for you, Lord Emiya, would even knowing he exists be a luxury we couldn't afford?"
This whole situation was deeply unsettling. He'd believed Shirou, of course, but seeing his brother die, come back, and casually drop a message from a literal god was a shock that rattled him to his core. A god really existed. A god who couldn't interfere. And a god who wasn't omnipotent.
And a danger greater than Madara Uchiha?
"What could possibly be more troublesome than Madara?" Tobirama couldn't help but ask.
"It's an unspeakable secret," Hashirama said, shaking his head gravely. "The Sage said we will only know when the crisis truly arrives."
"So, you're still going to die," Tobirama stated, the reality crashing down on him again. "The Sage was willing to give you a few more moments of life, just to apologize to Lord Emiya?"
"That's right," Hashirama nodded slowly. Even the Sage of Six Paths greatly respected Emiya Shirou. It was a strange thought. People imagined a god as high and mighty, but the Sage was apparently quite approachable, even respectful towards a mortal, just like them.
"Tobirama, do not leak this secret," Hashirama instructed, his gaze shifting between his brother and Shirou. "The Sage also hopes that you, Lord Emiya, can keep the secret about him and the underworld."
Shirou's brow furrowed slightly. "I've already learned to conceal things in this era. You needn't worry."
"That really makes us ashamed, hahaha," Hashirama laughed, a bit embarrassed. Because this whole thing really was embarrassing.
The Sage had told him a little about Shirou's history, the ancient dispute over chakra, and how Shirou had ultimately backed the Sage's successor, Asura, only for it to end badly.
Come to think of it, Hashirama recalled the Sage's gaze lingering on him for an uncomfortably long time during that part of the story.
That Asura was unfair to Shirou... so perhaps I should take some of that unfairness upon myself.
After all, Tobirama had disturbed his soul's peace. As the older brother, he should bear that responsibility.
"Tobirama," Hashirama placed a hand on his brother's shoulder. "You must send Lord Emiya's soul back to the Pure Land. You are never to use that evil forbidden jutsu to disturb his peace again."
"Yes, brother," Tobirama sullenly agreed. Though he hadn't fully plundered the treasure trove that was Emiya Shirou, Konoha had benefited greatly from his medical skills. And anyway, summoning him in the first place had only been to treat his brother.
"It's alright," Shirou said, unbothered. He gently adjusted the sleeping Tsunade in his arms. "If I wanted to return to the Pure Land, I could have undone this jutsu myself long ago. It's just that..." His gaze fell on the little girl. "I have now found hope for the succession of medical ninjutsu in this world."
"Little Tsuna, huh," a smile touched Hashirama's lips. "It seems her luck is really enviable."
He patted his brother's shoulder one last time. "Alright, I have to go. And you don't have to worry about what happens after I die. The Sage will guide my soul to the Pure Land, so I won't be trapped between worlds because of my attachment to Madara."
Tobirama's mood immediately improved. If his brother could find peace, it would alleviate much of his own guilt. For so long, he had forced his brother to make painful choices, all for the sake of the village. In the future, that would no longer be necessary.
Just as Tobirama wanted to say a few more words, the hand on his shoulder suddenly went limp. His brother's body fell once more.
Tobirama caught him. But this time, he knew, his brother would not wake up again. Their plan had succeeded, in a way. He'd even met the Sage. But in the end, it changed nothing.
"I'll take Tsunade and go first," Shirou said, his own mood far from calm. It seemed his grand performance had successfully deceived the Sage.
The god-like being hadn't interfered with his desire to stay in the living world, nor did he seem to have the power to do so easily. His test had, more or less, achieved its purpose. If the Sage wasn't going to interfere through Hashirama, then his future plans would have to rely on the next reincarnations of Asura and Indra's chakra. Uzumaki Naruto and Uchiha Sasuke. The true targets of his thousand-year plan.
Next, he had to use this to influence Black Zetsu, leveraging the Sage's "existence" to force the creature to give up on using him as a sacrifice. As he was thinking, he picked up Tsunade and turned to leave. A new request had just appeared.
S-Rank Request: Obtain Hashirama Cells.
He accepted it without much thought. [Unfinished Requests (3/3)]. He looked at the little girl in his arms. He had no intention of desecrating Hashirama's remains. There was another, much easier source of Hashirama cells: Madara Uchiha.
For Shirou, obtaining them from Madara would be simple. Besides, he knew Tobirama had already collected and sealed away his brother's cells in a lab somewhere. There were options.
When Mito saw him walk out of the house with Tsunade, she knew. The red-haired woman's will was like iron. She didn't rush in to see her husband. Instead, she bowed deeply to Shirou.
"My condolences," Shirou said, lowering his head slightly.
"Thank you, Lord Emiya, for everything you've done for my husband," Mito replied, her brow furrowed with the effort of holding back her tears.
A rare hint of apology touched Shirou's face. "My plan still failed."
"No," Mito shook her head, genuine gratitude in her eyes. "I can sense the change in him. This is not your fault. Kurama has already told me everything. It guessed your plan."
Her sensory abilities were strong. She had felt a strange, terrifying wisp of chakra appear in her husband's body. Kurama, despite its dislike for Hashirama, had told her its source: the Sage of Six Paths. Even a god could not save her husband.
"Tsunade..." Mito looked at the peacefully sleeping child. "I'll have to trouble you to take care of her for a few days."