After engraving his own redesigned Flying Thunder God marks onto two teacups, Kei maintained his hand signs, carefully sensing the spatial markers with high precision as he attempted to perform the Flying Thunder God.
He guided his chakra along a specific chakra path, using his personal Flying Thunder God marks as an aid. With his natural talent for ninjutsu, combined with the enhancement from the trait [Shout and It Comes], which amplified his chakra control, and [Spatial Insight], which provided high compatibility with space-time ninjutsu, he quickly grasped the technique.
After only a few failures, he successfully completed his first spatial teleportation.
"It's like stepping through one door and entering another... Spatial jumps are actually this simple to achieve... Tobirama was truly a genius!"
A deep admiration filled Kei as he thought about the technique's creator. To have developed such a ninjutsu in his youth, slain Izuna who was a wielder of the Mangekyō Sharingan, and left behind countless forbidden jutsu in Konoha… If Tobirama hadn't died so early, who's to say he wouldn't have surpassed even Hashirama?
With each activation of the Flying Thunder God between the two spatial markers, Kei quickly familiarized himself with the sensation of space-jumping. At first, the technique required several seconds of preparation, but after just a few dozen practice attempts, the time had already been cut down by more than half.
However… the chakra consumption was brutal.
Feeling his chakra drain like floodgates bursting open, his whole body tingled from the strain.
In terms of jutsu ranking, the Flying Thunder God Technique wasn't actually that energy-consuming. A single short-distance teleportation within ten meters, only involving one person, used just a bit more chakra than casting a C-rank Fire Release: Great Fireball Technique.
But the problem was… who only teleports once in a battle?
Take Pakura's fight against the Kiri ninjas as an example. If ten or even twenty Flying Thunder God kunai were thrown, who could guarantee that each kunai would land near an enemy?
Combat wasn't just about teleporting close to an opponent to launch an attack; it also required dodging enemy strikes and repositioning the Flying Thunder God kunai. Even in an ideal scenario where every enemy was killed upon first engagement, at least thirty teleportations would be needed per battle.
Firing off thirty C-rank Great Fireball Jutsu in rapid succession would exhaust a typical jonin's chakra in minutes. Even Kei was starting to feel the drain.
Despite having the [Transmigrator] trait, which greatly boosted his spiritual energy, seven to eight times higher than a normal jonin, and a body strengthened through years of training, making his chakra reserves roughly three times that of an average jonin, he still found it hard to sustain.
In the original story, even a post-time-skip Kakashi, weakened by the burden of his Sharingan, had chakra levels slightly below the jonin average.
"Chakra Storage… Ultra-Fast Reactions…"
Rubbing his chin, he realized that to fully unleash the power of the Flying Thunder God, he would likely need two more traits.
A vast chakra pool would significantly increase the technique's sustainability and margin for error. Meanwhile, reaction speed far beyond that of ordinary ninjas would directly raise the technique's upper limit.
The pace of ninja battles was incredibly fast.
For the strongest fighters in the shinobi world, the openings and weaknesses they revealed during combat were fleeting, disappearing in an instant.
With [Ultra-Fast Reactions], he could seize those fleeting weaknesses in battle, drastically reducing the number of teleportations needed and minimizing the risk of getting countered due to predictable movements.
"Chakra Storage is fine, just a blue trait. If I get the chance, I'll copy a higher-tier one. But Ultra-Fast Reactions? That's a must-have!"
"Without it, I'll be like Kakashi using Chidori without a Sharingan—fast as hell but running blind."
"Tch—now I get why Tobirama didn't massacre enemies left and right like Minato with a chain of Flying Thunder God teleports. Guess even he couldn't react fast enough."
As these thoughts ran through his mind, he continued practicing the Flying Thunder God Technique. He only stopped when his chakra reserves dropped below half, taking a moment to deal with the two teacups engraved with his Flying Thunder God marks.
This was not a technique he intended to reveal until he could wield it smoothly in actual combat. At the end of the day, ninjutsu existed to kill. Showing off prematurely would only alert potential enemies.
Besides, his mastery of Yin Release was already enough to dominate any opponent below Kage-level.
If he had been in Pakura's situation earlier today, facing that ambush…
With his full power unleashed and the unpredictable nature of Yin Release, he could have wiped out half of them in the first exchange. Cleaning up the rest would take a little effort but wouldn't leave him injured or struggling. No need to wait for reinforcements, no need to end up battered and bruised.
After all, whether it was high-level secret techniques from the Yamanaka clan or various genjutsu, they were all designed to crush weaker opponents effortlessly.
A sudden burst of intense spatial fluctuations rippled from where Minato had left. A thick chakra smoke erupted in the room.
Pale-faced and looking like he had been corroded by some unspeakable force, Minato stumbled back into the room, one hand gripping the wall, the other clutching his stomach. His expression contorted in pain, as if he were barely holding something back.
"... You can't be serious."
Kei blinked at his friend, half of his usual teasing mood vanishing at the sight of Minato's suffering.
"Red ones… green ones… purple… pink… long ones… oval ones… ugh—!" Minato barely got the words out before his mind was flooded with images of the 'feast' from Mount Myōboku.
He nearly vomited on the spot.
"Why not think of something better? Hmm… insect protein is six times higher than beef… tastes like chicken… crunchy?"
"Kei! Ugh—! You know what that damn Mount Myōboku feast is like! Ugh—!"
"You're the one who believed Jiraiya's nonsense and signed that contract. What's done is done. If you can't change it, why not just lie down and enjoy the ride?"
Minato couldn't even finish his sentence before he bolted to the bathroom, where the sounds of violent retching soon followed.
When he finally dragged himself back to the living room, looking completely drained, Kei clapped his hands.
"Alright, now that you've emptied your stomach, let's think about what to eat for dinner. I haven't eaten yet."
"You're a demon." Minato's already broken expression shattered further.
He genuinely couldn't understand.
At what point in his life had he messed up so badly that he believed Kei was a good person and willingly became his friend?
All these years, how many disasters had he suffered because of this menace?