For the next stretch of time, Watanabe Ichiro threw himself into learning the [Flying Thunder God Technique] with all the enthusiasm he could muster.
But honestly, this thing was downright insane.
He had no idea how Flying Thunder God worked in the original story, but in this world, the version Tobirama Senju had developed was somewhat like teleportation in an online game.
The world's time and space were constantly shifting, and the shinobi world actually followed proper rules of orbital revolution and axial rotation.
First, the Flying Thunder God Formula had to be imprinted on an object to serve as a sensory coordinate.
Then the world had to be divided according to certain rules to produce positioning data, such as [203,134,145].
On top of that came formulas accounting for the shinobi world's revolution and rotation, plus some conversion formulas that Tobirama Senju had somehow managed to calculate.
Finally, chakra was used to link those coordinates to the sensory coordinates of the Flying Thunder God Formula and activate it.
The most insane part was that all those steps had to be completed within one second. Any longer, and the world's positioning data would change, forcing him to calculate everything again.
Hello, I'm a human, not a computer, thank you!
With a miserable expression, Watanabe Ichiro began memorizing formulas and speed-calculation methods, before finally deciding-
Time to bring in the system. Fight technology with technology!
He negotiated with the system and spent points to have it handle Flying Thunder God's calculations. His dear, adorable system optimized the interface UI, so now all he had to do was scatter Flying Thunder God Marks. Their locations and notes would appear in the bottom-left corner of the system interface, and he only needed to supply enough chakra.
As a result, his learning progressed by leaps and bounds, to the point that even Tobirama Senju called him a freakish learning genius.
Recognizing Watanabe Ichiro's exceptional talent, Tobirama Senju began to consider something.
He had personally brought Watanabe Ichiro back. The boy had lived and studied in Konoha since he was four. Though his background and appearance had always made him unpopular with his clansmen, and he had no close friends, he had remained modest and mild-mannered, yielding to others at every turn.
Tobirama had sent people to test Watanabe Ichiro several times.
When Watanabe Ichiro had first joined the Anbu and was still weak, they had deliberately made things difficult for him and beaten him several times without justification.
Yet the boy had merely thanked his seniors respectfully for their instruction, then gone back to train even harder.
Even after his strength surpassed those seniors who had bullied him, he had never retaliated. During sparring, he held back and stopped once he had made his point.
(Watanabe Ichiro: No, I actually got revenge behind their backs. I used system items to make them impotent for a year. Every one of them who had a girlfriend got dumped. Ha.)
Gentle and generous by nature, with the capacity to tolerate others; bright and talented, with an exceptional ability to learn.
Perhaps...
Tobirama Senju watched Watanabe Ichiro, who was overwhelmed by the choices in a thick stack of [Forbidden Technique Sealing] scrolls, and spoke.
"Uchiha Ichiro, would you like to become my personal disciple?"
At last, he had set aside his prejudice against the Uchiha, breaking the psychological shackles left by nearly twenty years of fighting them to the death.
Being a personal disciple offered many advantages over being an ordinary student, but the most important one to Watanabe Ichiro was this: he could openly study the forbidden techniques Tobirama Senju had developed over the years. He no longer had to pretend to agonize over his choices while secretly using the [Detection] he had previously bought from the system to transcribe them into it and study them later. (He had bought the [Transcription] skill earlier, while snooping through the scroll about Hashirama Senju's return to Konoha.)
More importantly, he could use these forbidden techniques in front of people outside Konoha. With Tobirama Senju backing him, he had no need to worry about being criticized.
Likewise, he could freely use his system skills. If anyone questioned him, he could invoke Tobirama Senju's name and claim that inspiration from one of his teacher's forbidden techniques had led him to develop a jutsu of his own.
The shinobi world was too dangerous-bring Tobirama Senju along! A forbidden-technique-brand Water Release master-make that an Ocean Release master-was just what you deserved!
Watanabe Ichiro had no reason to refuse. He promptly accepted Tobirama as his teacher and received a piece of news that made Black Zetsu deeply uneasy.
Because of Watanabe Ichiro's changes to the timeline, Tobirama Senju had begun researching [Impure World Reincarnation] much earlier and devoted more effort to it. The initial prototype was already complete, and Tobirama Senju planned to begin attempting to summon the dead the following week.
If this Technique Formula successfully summoned Uchiha Izuna, and he came bounding out alive and well, would Madara Uchiha still want to activate Infinite Tsukuyomi?
Black Zetsu did not want to gamble on that. He planned to sabotage the ritual, lurking nearby to eavesdrop on the arrangements and plans for a long time as he prepared to play dirty.
A week later, inside Tobirama Senju's laboratory.
The first experiment with Impure World Reincarnation was about to begin.
Tobirama Senju checked the preparations one by one.
He had already sent his elder brother, Hashirama Senju, away to a meeting under the pretext of official business. He had specifically instructed the clan heads attending it to keep the meeting going until the experiment ended, even if they had to put their necks on the line. Otherwise, his brother, who had always opposed using living people as experimental subjects and sacrifices, would certainly interfere and seal the Technique Formula away.
The living sacrifices-the death-row prisoners-were in place.
The cultivation of Uchiha Izuna's cells was complete.
The Technique Formula had been calibrated.
With everything ready, Tobirama Senju nodded to Watanabe Ichiro, who placed the items in their designated positions as previously instructed.
Tobirama Senju focused and raised his hands to form hand seals.
Tiger, Snake, Dog, Dragon, then finally, he brought his hands together.
The Technique Formula activated.
Black Technique Formulas appeared on the ground and quivered like tadpoles, slowly linking together to hold the death-row prisoner serving as the sacrifice firmly in place. The runes gradually formed orderly arrays out of scattered individual symbols, ultimately creating a large ritual array with a distinctive beauty.
Watching from the side, Watanabe Ichiro silently reflected that this experiment would most likely fail.
Nothing seemed wrong on the surface, but the marker representing Black Zetsu on the system overlapped perfectly with the array before him. There was no need to think twice-that bastard was definitely hiding underground, causing trouble.
Sure enough.
The Underworld Creation rising from underground had barely broken the surface when the runes themselves began trembling uncontrollably and slowly retracting.
Tobirama Senju frowned deeply, changing the Technique Formula in his hands as he tried to stabilize the runes.
Just as Tobirama Senju was doing everything he could to salvage the situation, Black Zetsu moved. He slowly approached Watanabe Ichiro and stopped beneath a rune that had been close to Ichiro's feet when he helped position the sacrifices.
Then, somehow, a corner of that rune vanished into thin air.
There was no question that Tobirama Senju would discover this spot when investigating the experiment's failure. Then he would recall where everyone had been standing... Well, he probably would not even need to recall. This experiment was so important that Tobirama Senju had sent everyone else away beforehand, leaving only Ichiro to help.
One of the two "people" present had sabotaged the experiment. If it had not been Tobirama Senju, who could it have been? Even children at the Ninja Academy could figure that out!
His current disguise, "Uchiha Ichiro," had no ability to detect or track Black Zetsu. He had no way to explain himself and could only let Black Zetsu frame an innocent man.
Well, well, Black Zetsu, you old bastard. I'm standing right here, and you're pinning the blame on me? You're screwing me over right in front of my face!
Still, Watanabe Ichiro did need a few rounds of suspicion and trust, crises and conflicts, to bring him closer to Tobirama Senju. After that, he would find a way to witness Tobirama's death or severe injury, giving him a "reasonable" excuse to awaken the Mangekyo and keep Black Zetsu by his side.
So he said nothing, going along with things and becoming the poor, falsely accused victim. At least he would not have to come up with the script himself.
But I'm remembering this grudge. Just you wait, Black Zetsu, you old bastard. You'll get what's coming to you.
Before you continue