Yin Release
Sasuke paused when he saw two Tōmas standing in the room.
He understood Shadow Clones well enough. Naruto had demonstrated them in front of him countless times. Normally, for a clone to pass information back to the original, it had to disperse.
Yet here, the clone was calmly handling paperwork, while the real Fujimoto Tōma had already arrived knowing Sasuke was there.
That meant this clone was… different.
Sasuke glanced at the "clone" working nearby. It was far more refined than he'd expected.
"Sasuke," Tōma said without wasting words, "I need your help with something."
"My help?" Sasuke's eyes lit up, and he smiled. "Of course."
Up until now, it had always been Tōma helping him. From guiding him, to pulling him back from the edge, to even helping him grasp Sage Mode. Sasuke had never really felt he'd repaid that debt.
So when a chance finally came to help Tōma instead, there was no way he'd refuse.
Tōma smiled, then after a moment's thought, brought Sasuke somewhere else.
When they arrived, Sasuke froze.
In front of him was a massive slug, so enormous it dwarfed mountains.
"This is Shikkotsu Forest," Tōma explained calmly. "One of the Three Great Sage Regions. Same type of place as Ryūchi Cave, where you trained before."
Sasuke nodded slowly. He'd guessed as much, but seeing the Slug Sage in person was something else entirely.
"Only the Slug Sage lives here," Tōma continued. "The area's huge, and no one bothers us. The number of people contracted with this place is extremely small."
Sasuke understood. As far as he knew, Tsunade was the only confirmed contractor. Sakura, maybe… and possibly Hinata or Ino now, depending on how things had shifted.
"Tōma," Sasuke said, refocusing, "what did you need me for?"
"Other than the kunai you gave me," Tōma asked, "do you have any other permanently marked ones?"
"I have one more," Sasuke replied, a little puzzled, as he took it out.
Tōma accepted it, then produced a scroll and began inscribing a formula.
A short while later, he tossed both back.
"This is?"
"A variation of sealing and summoning techniques," Tōma said. "It lets you summon objects. That way, even if you swap positions at long range, you won't lose your kunai."
Sasuke nodded. That matched what he'd guessed.
"The technique isn't complicated," Tōma added. "My clone can teach it to you later. Even if you don't fully grasp the theory, you can replicate it. Once you create new kunai, you can inscribe them yourself."
"Got it," Sasuke replied.
He'd spent years chasing raw combat power for revenge, neglecting other areas. It was time to fill in those gaps.
Then Tōma finally explained why he'd brought Sasuke here.
Just like before, when he'd used Naruto's body to experience Mount Myōboku's Sage Mode, he now wanted to use Sasuke's body.
But this time, it wasn't about Ryūchi Cave.
It was about the Mangekyō Sharingan.
Tōma wasn't coveting Sasuke's power. Rather, the Mangekyō represented the pinnacle of the Sharingan's evolution. More importantly, it was the purest manifestation of Yin Release.
Tōma had been studying Yang Release for a long time. Yin was the missing half.
Amaterasu. Tsukuyomi. Susanoo.
All of them were creations of Yin Release.
Yang Release governed physical vitality and life force. Tōma already had a deep grasp of that. His endurance, recovery, and raw life energy had reached absurd levels. In simple terms, his "health pool" was massive, and it regenerated quickly.
Ironically, he'd never needed to use it to survive anything serious.
Yin Release, by contrast, was power born from imagination and spiritual energy. Creating form from nothing.
Tōma had some experience with it through genjutsu and the Spirit Transformation Technique, but those were still just techniques. Fully understanding Yin Release that way would take too long.
The Mangekyō Sharingan, however, was condensed Yin Release at its purest.
"So," Tōma said, "I'm going to use the Spirit Transformation Technique to borrow your body and activate your Mangekyō."
Sasuke nodded without hesitation.
It only reinforced his belief that Tōma never stopped thinking about how to grow stronger.
"Don't resist," Tōma said.
His body slumped slightly as his consciousness left it.
Moments later, Tōma entered Sasuke's body.
The first thing he noticed was Sasuke's mental strength. It was far tougher and more refined than that of ordinary shinobi.
That was expected.
Awakening the Mangekyō through one's own resolve required immense spiritual power. Sasuke hadn't relied on artificial trauma like most Uchiha. That alone explained the stability of his mind.
Other Uchiha often awakened their eyes through extreme emotional shocks. Killing loved ones. Losing comrades. That kind of repeated stimulus almost guaranteed mental instability.
It was no wonder so many of them went to extremes.
Even Sasuke felt it now.
Sensing Tōma's spiritual presence, he fell silent.
Why is his mental power this strong?
Sasuke had endured childhood trauma, awakened the Mangekyō, and yet his mental strength still didn't surpass Tōma's.
For a fleeting moment, he wondered if Tōma had been born an Uchiha. If so, he might've awakened the Mangekyō even earlier than anyone in history, without needing trauma at all.
In the end, Sasuke could only sigh inwardly.
Truly strong people had no weaknesses.
Against Tōma, Sasuke couldn't see even the slightest chance of victory.
Once he'd fully adjusted to Sasuke's body, Tōma formed a familiar hand seal.
The next instant, "Sasuke" opened his eyes.
Three tomoe spun slowly within them.
"Sharingan."