It wasn't just about ambushes. As Uchiha Shinji let his thoughts wander, he realized this dojutsu would also be exceptional for escaping.
Suppose Yakumo encountered a powerful enemy and couldn't break free.
She could simply have Ido flee in spirit form, then activate the dojutsu to swap places with Ido once she reached a safe location.
Caught off guard, most enemies wouldn't be able to intercept Ido in her spirit state, allowing her to escape effortlessly thanks to the advantages of being a spirit.
Of course.
All of this hinged on one condition: Ido, in her spirit form, truly being able to coordinate with Yakumo to activate the dojutsu. If that couldn't be achieved, then it was all moot.
So Uchiha Shinji reined in his thoughts and, through "Jikibi," instructed both Yakumo and Ido at once, "Try activating that dojutsu again!"
"But I just dispelled—"
Mid-sentence, Ido caught on, realizing Uchiha Shinji was testing whether she, in her spirit form, could assist Yakumo in triggering the dojutsu.
Then it hit her—if she could cooperate with Yakumo in spirit form, the technique's flexibility would increase dramatically.
Whoosh.
In an instant, Ido, who'd been in spirit form before Uchiha Shinji, transformed into the physical form of Yakumo.
"It really works…"
Uchiha Shinji was quietly astonished.
With this successful attempt, it meant Yakumo now had a spirit that could freely designate teleportation coordinates within a 50-kilometer radius.
As long as she used it well, whether for ambushes or retreats, she'd handle it with ease.
And if she wanted Ido to operate at an even greater range, all she'd need was to give Ido a physical blood clone, enabling ultra-long-distance spatial teleportation.
As he pondered, Uchiha Shinji's gaze fell on Yakumo, who stood before him, brimming with joy.
The Yakumo of today wielded Koryugan's powerful perception and insight abilities and could manipulate and influence an enemy's blood.
At the same time, she'd split off Ido and mastered the Kurama clan's illusions—potent enough to blur the line between reality and fantasy.
On top of that, she'd endured the First Hokage's cell transplant surgery, overcoming her innate frailty, and gained "Wood Release," a power that struck fear into the other four great shinobi villages. She'd also apprenticed under Tsunade, learning the Senju clan's "Strange Strength Fist."
And now, she'd mastered a space-time ninjutsu, allowing her to strike any target she wished to ambush without a trace.
"What kind of monster have I created…?"
The more Uchiha Shinji thought about it, the more alarmed he became.
Any single one of Yakumo's abilities would be enough to propel a shinobi into the ranks of jonin, yet she possessed them all at once.
She didn't even need to learn or develop new ninjutsu anymore. Simply mastering what she already had would effortlessly elevate her to Kage-level strength.
Yakumo, elated, said, "Leader, Ido really can coordinate with me to activate 'Koryu' in spirit form—we did it!"
"So this dojutsu is called 'Koryu,' huh?" After a brief sigh, Uchiha Shinji's expression turned serious as he cautioned Yakumo, "Space-time ninjutsu is different from other techniques. When you and Ido use it in the future, you must be extra careful."
"Yes!"
Seeing Uchiha Shinji grow stern, Yakumo immediately wiped the smile from her face.
Uchiha Shinji continued, "Also, spirit form isn't invincible. Many barriers, sealing techniques, illusions, and even certain special ninjutsu can harm spirits. So don't think that mastering 'Koryu' means you can act recklessly."
"I'll remember that!"
Yakumo took it to heart.
"Alright, swap back for now. Today's testing is over!"
After sending Yakumo and Ido off, Uchiha Shinji quietly returned to the village.
This round of testing had not only confirmed that Ido, when controlling a blood clone, could move freely without restriction, but also unexpectedly yielded a space-time ninjutsu—a bountiful harvest indeed.
The only downside was that "Koryu," this space-time ninjutsu, was deeply tied to Yakumo's abilities. If someone else used it, its effectiveness would be greatly diminished.
Even Uchiha Shinji wasn't exempt.
Since "Jikibi" could only link to spirits, not blood clones, he couldn't achieve the same long-range sensory communication as Yakumo and Ido.
Of course.
For now, Yakumo and Ido's long-range communication wasn't yet seamless and required Uchiha Shinji to bridge them with "Jikibi." But once they grew proficient, they'd be able to sense and coordinate without it.
The next day.
After attending morning classes at the shinobi academy, Uchiha Shinji skipped the afternoon session and headed straight to Hidden Leaf Hospital to continue studying Tsunade's fusion and suppression formula.
It wasn't until evening that he emerged from his lab, yawning.
Just as he was about to leave Hidden Leaf Hospital, a figure appeared before him. "Excuse me, are you Uchiha Shinji?"
Uchiha Shinji glanced at the person, then nodded calmly.
The other adjusted the glasses on their nose bridge and smiled politely. "Hello, I'm Yakushi Kabuto. I officially joined the medical team today."
"Hello, Uchiha Shinji."
Uchiha Shinji returned the greeting, but inwardly, his guard went up.
He knew better than anyone who Yakushi Kabuto was, and Kabuto's presence here meant Orochimaru's eyes were undoubtedly fixed on this place.
Leaving Hidden Leaf Hospital, Uchiha Shinji cast a glance back before retracting his gaze.
For now, he wasn't sure whether Kabuto had infiltrated the medical team to target Yakumo or himself.
Yakumo's awakening of Koryugan and her First Hokage cell transplant surgery were both things that could catch Orochimaru's interest.
And his victory over Yakumo in their spar could similarly draw Orochimaru's attention.
But he'd already factored this in when he allowed Yakumo to reveal Koryugan.
With Tsunade's protection, as long as Yakumo didn't leave Hidden Leaf, no ordinary person could harm her.
As for himself, he was no longer the pushover he once was. Whether it was Orochimaru or Danzo, anyone trying to trouble him now would find it far from easy.
Truth be told, if it weren't for the imminent "Rinnegan Plan," he could take action against Kabuto right now, eliminating Orochimaru's spy in the medical team.
But with the fully damaged Mangekyo Sharingan in Karin's eye sockets nearing recovery and the "Rinnegan Plan" about to officially begin, he didn't want to stir up unnecessary trouble at this juncture.
After all, he still wanted to stay in the medical team, secretly studying Tsunade's medical ninjutsu using their resources and equipment.
Back at his apartment, to be safe, Uchiha Shinji first used "Jikibi" to warn Yakumo, telling her to be cautious of Yakushi Kabuto.
Then he contacted Karin via "Jikibi" and asked, "How's the Mangekyo's recovery going today?"
Suppressing her excitement, Karin replied, "Leader, I can see blurry shapes now!"
Uchiha Shinji's tense heart finally eased.
If the earlier light sensitivity only indicated that the fully damaged Mangekyo had regained some activity, this imaging now confirmed that the pair was truly starting to regain functionality.