Sometimes, it's better not to speak too plainly.
Emiya Shigen couldn't directly tell Senju Tobirama, "Just fully revive me, and I can heal your brother."
Tobirama was naturally suspicious. If Shigen made his intentions too obvious, Tobirama would inevitably suspect that this resurrection was part of some grand scheme.
Which, of course, it was.
Because it was a scheme, Shigen needed to carefully nurture it over time. A well-crafted plan takes patience to unfold. If rushed, the entire conspiracy would fall apart.
But Tobirama...
Tobirama didn't seem to care at all about whether Shigen could achieve true resurrection. Instead, he was more concerned about the mysterious Yang Release that Shigen had mentioned.
"Lord Emiya, what exactly is this 'Yang Release'?"
Tobirama furrowed his brows as he pondered aloud.
"This seems to be related to Yang chakra. I recall that Yang chakra can be used to create various powerful secret techniques, and medical ninjutsu often involves manipulating Yang chakra..."
For instance, the Akimichi clan in Konoha.
Tobirama knew that the Akimichi specialized in using Yang chakra to perform their signature Expansion Jutsu, which allowed them to temporarily enlarge their bodies and increase their strength.
"You're right."
"Yang Release is the pinnacle of Yang chakra."
Emiya Shigen patiently explained the concept of Yang Release, weaving his words to subtly tempt Tobirama.
"With Yang Release, one can create life out of thin air. It can regenerate lost limbs and quickly heal damaged organs. And naturally..."
Shigen's gaze drifted toward Hashirama, lying unconscious on the bed.
"...it can restore life to those whose vitality has been depleted. It can let them keep living."
Tobirama's eyes lit up with curiosity.
"Then..."
He asked the most crucial question.
"How can a ninja refine their Yang chakra to its peak and obtain this 'Yang Release'?"
"That's not easy."
Shigen's eyes gleamed briefly as he sighed, playing his role perfectly.
"The simplest way is for someone who already possesses Yang Release to share their power with another person."
"And your brother..."
"...is the most suitable candidate to receive my Yang Release."
Shigen raised his hand, where a faint green glow of chakra briefly flickered before fading.
"Unfortunately, when I was resurrected, my Yang Release vanished without a trace. I have no idea why."
"..."
Tobirama took a deep breath.
"I apologize."
"It must have been my mistake."
Tobirama bowed his head slightly, taking responsibility.
"The issue likely lies in my Edo Tensei technique. This was my first time using it..."
"It's fine."
Shigen didn't blame him. Instead, he gently dug the trap deeper.
"Perhaps it's because this body isn't my original one. Or maybe my Yang chakra simply dissipated in the afterlife..."
Tobirama nodded thoughtfully.
"???"
Shigen internally raised a giant question mark.
Wait, what?
You really think this is my fault?
No way.
The problem is obviously with your sloppy jutsu, not with me, an ancient expert!
To ensure the Edo Tensei ritual would succeed, I deliberately lingered in the afterlife and willingly answered the summon.
If I hadn't cooperated...
There's no way your clumsy jutsu would have worked!
This is giving me a headache, Shigen thought.
Given the circumstances, Shigen decided to play along for now.
At least this gave him a valid excuse to remain in the living world.
Even if he was bound to his Edo Tensei body, he could bide his time. There would be other opportunities to achieve a true resurrection.
"Let's leave it for now."
Shigen sighed as he looked at Hashirama's unconscious form.
"I'll try a different medical approach first. I'll attempt to suppress his chakra and stop his self-healing ability from causing his cells to divide too rapidly."
"That won't be easy."
Tobirama agreed with Shigen's method but remained skeptical.
"My brother's chakra is incredibly strong. Suppressing it will be difficult."
"Indeed, it's very strong."
Shigen raised a finger, which now glowed with a dark, ominous chakra.
"It's almost on par with your ancestor, Asura."
"What's that?"
Tobirama's expression turned serious.
"A curse mark."
Shigen explained calmly.
"This mark is formed by natural energy. It suppresses the target's chakra. If they try to use chakra recklessly, the curse will paralyze them."
"But I'm not sure if it will work on him..."
Shigen's tone was cautious, as if he wasn't entirely confident.
"Your brother has traces of Sage Mode in his body. His cells might adapt to the curse mark's energy too easily, making it ineffective."
"Natural energy...?"
Tobirama's interest was piqued.
"Could you let me examine it?"
"I have some understanding of certain techniques. Perhaps I could help refine it."
Perfect.
Shigen thought this was the ideal scenario.
Tobirama was naturally cautious, preferring to verify things for himself.
Even though he trusted Shigen, he couldn't fully trust anyone when it came to his brother's life.
"I'm just a bit worried," Shigen murmured, his expression growing slightly anxious.
"Is there a problem?" Tobirama asked, raising an eyebrow.
"This isn't a conventional medical technique," Shigen explained sincerely.
"While the curse mark temporarily seals someone's chakra, if the marked person fully masters it, they'll gain even stronger chakra."
"I worry..."
"...that spreading the curse mark might be like spreading chakra itself. It could become another tool for conflict."
Shigen sighed deeply, his voice filled with melancholy.
"When the Sage of Six Paths and Asura spread the concept of chakra to the world, many people feared it would be used for violence."
"But we believed that people would use chakra to help each other and ease suffering."
"Looking back now..."
"...we were wrong."
"Chakra has become a weapon for endless battles."
"Lord Emiya."
Tobirama's tone softened.
"That wasn't your fault."
He offered words of reassurance.
"The problem isn't with the power itself. The problem lies with the greedy hearts of those who refuse to be content."
"Rest assured."
"I won't spread the curse mark."
Tobirama raised his hand, making a solemn vow.
"And if I ever use the curse mark for conflict, may my soul never find peace in the afterlife!"
"...That's not necessary."
Shigen's eye twitched slightly.
Wait a second...
Tobirama...
Do you even hear yourself?
You invented Edo Tensei, a jutsu that literally disturbs the peace of the dead.
And you still think your soul will rest peacefully?
But since Tobirama had made such a serious vow, Shigen decided to go along with it.
"Very well."
Shigen carefully placed the curse mark on Tobirama.
After all...
If Tobirama ever discovered the truth and tried to undo Edo Tensei, this curse mark would give Shigen a way to counter him.