But in truth, Aoshi wasn't at all certain he could actually master the Flying Thunder God Technique. There was a very real chance he would waste his time and effort.
After all, in the original records, aside from its creator—Senju Tobirama—only Minato had ever successfully learned this jutsu. That alone proved just how impossibly difficult it was.
Even among space–time ninjutsu, it was considered one of the hardest.
Take the Summoning Technique, for example. It was also a space–time ninjutsu, yet its difficulty level was only C-rank—something any chunin could learn. With a summoning contract, even a genin could usually master it quickly.
On the other hand, Edo Tensei (Impure World Reincarnation), another S-rank forbidden technique, also fell under the category of space–time ninjutsu.
Its principle was essentially a forbidden version of Summoning, pulling the souls of the dead from the Pure Land back into the living world by binding them to a human vessel.
But compared to the Flying Thunder God, Edo Tensei was undoubtedly easier to learn. It was only forbidden because of its sheer inhumanity.
Still, "easier" was relative—it remained an S-rank forbidden jutsu. Even without being sealed away, ordinary shinobi would never be able to grasp it.
What made the Flying Thunder God so incredibly difficult was that learning it required not just talent in space–time ninjutsu, but also exceptional sensory perception and near-superhuman reflexes.
All three were absolutely necessary.
Even so, Aoshi chose the technique without hesitation.
Even if he failed, once Minato mastered it in the future, Aoshi could still rely on his system to obtain it. Choosing it now was a way of preparing early, ensuring he could use it later without issue.
"Very well. This is the scroll for the Flying Thunder God."
Seeing Aoshi's firm resolve, Hiruzen Sarutobi said no more. He could understand—geniuses always carried a certain pride.
He himself had once tried to learn the technique, but after months of effort without progress, he had given up.
So, before handing it over, he offered one final piece of advice.
"If you truly cannot learn it, you can always come to me and exchange it for another jutsu."
It was a rare privilege, a special courtesy granted only to talents like Aoshi.
Leaving the Hokage's office, both Aoshi and Tsunade, exhausted from the day's work, returned to their own homes.
Back at his place, Aoshi didn't immediately rest. Instead, he unrolled the scroll and began studying the Flying Thunder God.
Who knew—perhaps with his talent, he might succeed. But after a long night of study, he sighed and gave up.
"Forget it. Better to get some sleep."
It was clear—some things could not be mastered by effort alone.
Three days later.
Ota, an ordinary Konoha chunin, had suffered a severe injury during a mission. His right leg had been amputated above the knee.
Normally, a case this serious meant immediate retirement. Ota himself had resigned to that fate.
But then Aoshi and Tsunade appeared, offering him another option. He didn't have to retire. He could still remain a shinobi.
As the sole breadwinner of his household, Ota accepted without hesitation.
Aoshi and Tsunade extracted some of his cells and began cultivating them alongside White Zetsu cells.
Two days later, a perfectly functional right leg, grown from White Zetsu cells, was successfully transplanted onto his body.
It looked identical to his original leg. Anyone unaware of the truth would never believe it had been transplanted.
It was far beyond any prosthetic technology.
[You have successfully treated Ota. Reward: 1 Blue Orb.]
[Congratulations! You have obtained 1 Soldier Pill.]
When Ota stood again, tears streamed down his face.
"Thank you, Lady Tsunade! Thank you, Lord Aoshi!"
And he was neither the first nor the only one.
Since the two techniques had been introduced at Konoha Hospital, many shinobi had undergone the same procedure—every single case a success.
The results shook the village. Elders, clan leaders, and jonin alike marveled at the breakthrough.
Once again, Aoshi's name spread throughout Konoha. Of course, awe also bred envy and scheming.
Danzo, Orochimaru, and Hiruko each found their own ways to secretly acquire samples of White Zetsu cells, planning to study them in private and uncover their hidden secrets.
Aoshi knew nothing of this. Even if he had, he wouldn't have cared.
The cells they obtained were only the artificially cultivated ones, stripped of Wood Release potential.
The true samples containing Hashirama's power remained locked safely within Tsunade's research base—completely inaccessible to outsiders.
Given how dangerous Wood Release was, Aoshi himself had suggested this precaution, wary of both unscrupulous individuals and spies from other villages.
"Tsunade, are you free today?" Aoshi asked.
"After working for two straight years, and finally seeing results… I think we deserve a celebration."
Tsunade raised a brow, eyes narrowing slightly.
"So what you're saying is… are you inviting me on a date?" Her words carried a hint of resentment.
Their relationship had grown naturally through years of working side by side on the White Zetsu research. Yet in all that time, not once had Aoshi formally taken her out.
That was why, when she saw him spending time with Kushina, her reaction had been sharp—too sharp.
It wasn't about Kushina at all. It was about her own unspoken jealousy, born from an imbalance in her heart.
"Of course it counts. So then, my beautiful lady—may I have the honor of taking you on a date tonight?"
Aoshi's words left Tsunade utterly satisfied.
Without hesitation, she threw herself into his arms and pressed her lips against his, giving her answer through action rather than words.
Inside the cinema.
The hall, which could normally seat over a hundred people, was empty save for the two of them.
They were watching the same new film that Aoshi had once gone to see with Kushina. But having already seen it, his attention was not on the screen—it was on Tsunade.
And since there were no outsiders present, he grew much bolder than usual, drawing several playful scolds from her.
"You little rascal, you really can't keep your hands to yourself."
"Well, what can I say? Tsunade, you're so beautiful, so irresistible."
He spoke from the heart. He had always been fond of mature women with a commanding presence, and in front of Tsunade, he had no defenses whatsoever.
"Hmph, smooth talker."
Though she put on a look of mock disdain, deep down Tsunade was delighted. The imbalance she had once felt in her heart quietly dissolved away.
Before long, the movie ended.
Hand in hand, they left and went straight up to the top floor, entering the apartment Aoshi had arranged there.
The moment they stepped inside, Tsunade froze in shock.
The entire room was filled with beautiful flowers, petals drifting down from above in a gentle cascade.
At that moment, Aoshi slipped a finely crafted jade bracelet onto her wrist. "Do you like it?"