Hidden Sand Village.
Granny Chiyo watched Sakura extract the metallic poison from Kankuro's body within seconds.
She then used a hand seal, seemingly the beginning of a Genjutsu, to quickly stabilize Kankuro's injuries.
Her actions made their medical Ninjutsu seem utterly inadequate.
The poison they were helpless against was easily removed by Sakura.
"As expected of Sakura, she's amazing!" Naruto exclaimed, looking at Kankuro's slowly waking face.
Kakashi thought to himself, "She even learned Satoru's Genjutsu that deceives the body. Sakura truly has Genjutsu talent."
It was indeed the right decision to have Sakura train with Satoru for a period back then.
That was Satoru's secret technique; those without a certain level of Genjutsu talent couldn't learn this Ninjutsu.
It also required a thorough understanding of the human body to master.
"Is he Tsunade's disciple? Has even that woman's disciple's medical Ninjutsu reached this level?"
Chiyo fell into deep thought.
It was too shocking.
She was also a master of poisons, and this was the first time she had witnessed such effortless detoxification.
"Quickly ask him what happened."
...Hidden Sand Village commercial street.
A burly man with spiky hair appeared, wearing a cloak to ward off the sandstorms.
"Based on Sasori's actions in various places before joining Akatsuki, it seems I'll have to make a move this time."
The burly man was actually a Shadow Clone of Satoru using a Transformation Jutsu.
Through his intelligence network, he had already uncovered some information about Sasori.
Coupled with the actions of his Shadow Clones in various locations these past days, the intelligence gathered on some powerful Ninja had become even clearer.
After leaving Sunagakure, Sasori, for the sake of his so-called puppet art, assassinated many special Ninja throughout the Ninja World.
These individuals were all known or unknown Bloodline Limit holders in the Ninja World.
Due to the unique nature of Ketsuryūgan, some Ninja who awakened their Bloodline were disliked by their communities; some ignorant factions viewed Bloodline in the same way that ordinary Konoha villagers viewed Naruto.
This was due to the traditional culture of the Ninja World.
And Sasori hunted these Ketsuryūgan Ninja.
From the intelligence on this behavior, it was likely that all the puppets in Sasori's Hundred Puppets Performance were human puppets possessing different Ketsuryūgan and secret techniques.
The country Sasori had once destroyed was also found by him.
It was a small nation called the Land of Embers, possessing special materials where organic and inorganic substances coexisted, making them highly suitable for puppet creation.
The intelligence left in Konoha from the year the Land of Embers disappeared only stated, 'A country destroyed by a mysterious Ninja'.
Satoru deduced this from various aspects like the materials of the Land of Embers and the Ketsuryūgan holders, combined with the plot information from the original work.
He didn't know if Sasori would, as netizens in his previous life said, choose to die at his grandmother's hands out of a change of heart, letting others go.
"What if he hears the name of Captain Satoru and wants to collect me, the greatest art?"
Satoru thought shamelessly.
Of course, that was impossible; Sasori would want the bodies of Pain and the others!
His decision to send a clone this time was just a precaution, to prevent Sakura, Kakashi, and the others from all dying here.
Otherwise, his clone's goal would still be to search for the hidden Kara.
Swoosh! Swoosh!
Just then, several figures quickly streaked past him on the streets of Hidden Sand Village.
It was Kakashi, Naruto, and the others... Konoha Library.
"Misfortune also has its benefits, just like the ugly and poisonous toad, it carries a precious jewel on its head..."
"Luck is hindered, activity is restricted..."
"Yin Release creates form from nothing, manifesting things that do not inherently exist in the world, such as imagination... such as shadows... such as the mind..."
"Reaper Death Seal... uses a medium to link the misfortunes of two people. This is a special Yin Release nature transformation, manifesting misfortune and applying it to reality..."
"Although there are references, developing the nature transformation of luck and misfortune is a development without a defined timeline..."
Satoru and his three-year-old son were together poring over books in the library.
Although Keigo was a three-year-old child, seeing his father so persistent, he also put aside some of his own research to help him find a way to counter that Ninjutsu.
Though he also wanted to know how to break it.
And after these days, the father and son finally found a possibility: to develop a Ninjutsu with a similar mechanism, specifically designed to counter this type of Ninjutsu.
Satoru's exceptional Yin Release talent was the only breakthrough point they discussed.
Keigo didn't know how high Satoru's Yin Release talent was, but hearing his father say it was very powerful, he helped brainstorm in that direction.
When father and son work together, they can cut through metal.
Risking Ayame's scolding, the two worked tirelessly, forgetting to eat and sleep, and finally found a breakthrough.
That was Keigo's initial idea: since the stronger the killing intent, the stronger the rebound, then all one needed to do was achieve a mutual kill.
Satoru referenced the Reaper Death Seal, a mutual kill Ninjutsu taught by the Shinigami, and discussed it with Keigo.
Through their combined ideas and Satoru's practical application, they finally concluded that the Reaper Death Seal is a Yin Release nature transformation Ninjutsu that manifests misfortune and, through a medium, balances the scales of misfortune, thus leading to a mutual kill with the enemy.
As long as one side has a way to avoid a fatal blow, they can defeat the enemy.
"But Dad, developing this kind of nature transformation isn't that simple!" Keigo's mind was exceptionally sharp.
At just over three years old, he could provide ideas to Satoru.
He also knew that developing a Chakra nature transformation was not a simple matter.
"It's alright, I've already developed several Yin Release nature transformations.
No matter how difficult, I have to develop this one too."
Normal nature transformation development, like the five elements, takes ordinary Ninja two to three years to complete.
Yin Release is naturally more difficult, but Satoru's talent in Yin Release is exceptional; he had researched several before and was confident in developing this one again.
A nature transformation that manifests luck and misfortune.
"Dad, you're so determined and seem very confident. I'm afraid my future ultimate Chakra secret research will still need your help."
Seeing his father so confident, Keigo was already imagining himself grown up, with his father assisting him.
If his father could even develop this kind of nature transformation, it meant his father was extremely strong in this area and very suitable to be his assistant.
"Hey, you kid, I ask you for a little help, and you're already eyeing your old man, huh?
I'm a man who wants to retire early, don't always think about bossing your old man around.
You'll have to rely on yourself in the future."
Satoru patted his young son's head.
"Don't pat my head, I'll get stupid."
"We finally found a way to deal with it. Today, Dad will buy you your favorite thing. What do you want?"
"I want a laboratory that's at least five hundred square meters, with complete equipment. If it's all the latest technology from the Land of Lightning, that would be even better."
"Hmm? Even selling Ichiraku Ramen wouldn't be enough money."
"Sigh, then just buy me two lollipops!"
"Why two?"
"Because you'll definitely want one too, Dad."
"Haha, as expected of my son. Today's lollipops are on Dad!"