It only took Kaida 3 days to master the Uzumaki way of making seals, well at least the beginner ones, but if we compare, hundreds of shadow clones working on the seals individually, one can say the time was a year or something.
After three days of constant fuinjutsu practice, Reina finally agreed to go to the next level of fuinjutsu, the process of making arrays and the stage where one takes his first step toward becoming a seal master in fuinjutsu, a position that could be compared to the Jonin level ninja in terms of respect and power.
"Since you guys have learned the basic seals, it is time to take it up a notch and begin your introduction to arrays. The true use of fuinjutsu starts from here," Reina said, taking out a book from her storage seal. This time the book was twice the size of the previous one.
"Aunt, I have learned some of the fuinjutsu arrays already," Kaida said.
"I can see that, Kaida, otherwise you wouldn't have been able to learn the third encryption method so easily, but since I have decided to teach you guys, I have to do it honestly. Though you guys have to first sign this contract," Reina said, passing a contract to both Kaida and Yomi.
The content of the contract was simple: they will learn fuinjutsu techniques from Reina and are free to use them however they wished, but they couldn't teach them to anyone else without her permission, even if they had a very good reason for that. The price for breaking the contract was simple—if they tried to teach it to anyone else without her permission, they would feel excruciating pain and would be paralyzed for one full day.
"Mom, don't you think this is too harsh?" Karin asked, as she was reading the contract with Yomi as well.
"Well, in Uzushiogakure we used to have the death sentence as penalty for the breaking of such contracts. Compared to that, this is nothing at all. Also, I am sure they will not teach that without my permission anyway."
In other words, she was not going to change the contract at all, not that Kaida or Yomi wanted to change that. After giving a quick read to the contract, they swiftly pricked their fingers with the kunai and dropped their blood on the contract, and suddenly the letters of the contract started floating.
And like bugs, they started crawling up Kaida and Yomi's bodies. They were able to feel the cold ink on their skin; the whole experience was bizarre but fascinating.
After the text reached their hearts, all of it began to get concentrated on a single point not larger than the tip of a needle. After every letter was concentrated on the point, they felt a slight pain, like someone pricked a needle in their body, but it was difficult to tell where.
As soon as that happened, the mark disappeared like it was never present in the first place.
"What was that, Aunt?" Kaida asked. Unlike anyone else who would be quite freaked out in such a situation, he was deeply fascinated by it.
All of the powerful seals he knew before coming to this world, like the one Danzo used to control the Root ninjas, or the one Orochimaru used to take over the souls and bodies of the other people, was completely different from what he had learned till now.
Compared to them, what he just experienced now was eerily similar to them, something he wanted to learn for sure.
Reina looked at Kaida with a raised brow, her expression slightly wary—like a mother about to hand her child a blade too sharp for toys.
"That, Kaida, was a combination of fuinjutsu and what we call juinjutsu—curse seals."
Karin perked up at the word, but Reina continued before anyone could ask further.
"Fuinjutsu," she said, lifting her hand and drawing a symbol on the paper with a brush, her stroke was the definition of perfection, "is the art of sealing. It binds actions, energies, or objects to conditions. But juinjutsu—that's different. It doesn't just bind things... it binds people."
She paused, letting that settle in the air like a heavy weight.
"Juinjutsu targets will, intent, and the body's natural reaction to chakra. It crawls into your nervous system, reads your chakra flow, and embeds conditions that trigger responses. Pain. Paralysis. Rage. Even death."
Karin looked uncomfortable, but Kaida leaned forward. This was knowledge which was very important, not just because he wanted to learn that, but also because there were people out there who knew this and would definitely use something like that if given the chance.
"What you felt just now," Reina said, pointing at Kaida's chest, "was the seal imprinting a command directly onto your chakra network as well as your soul."
"So… it's like a living rulebook etched into your soul?" Kaida asked, eyes gleaming with fascination as well as slight tension.
Reina chuckled softly. "That's one way to put it. But remember this, Kaida—juinjutsu is not a toy. The Uzumaki created it to control beasts, criminals, and even other clans. It can protect… or enslave."
She looked dead serious now.
"Many feared us because of our juinjutsu. Even among seal masters, few dared touch it. For now, we will focus on fuinjutsu only, but if you show the talent to handle this as well, I may consider teaching juinjutsu to you as well." Reina saw the fascination in Kaida's eyes, and she was sure that he would ask her to teach him the curse seal technique for sure, so she gave the condition first. The juinjutsu developed by Uzumaki was among the few things which the world was not ready for, not once again.
Kaida nodded, his expression unreadable.
Inside, though, he was burning with the same fire that had pushed him to master genjutsu, kenjutsu, and now this…
Juinjutsu. Living seals. Something like this could very well be the thing he needed for what he had planned for the future, but for now, he had to focus on fuinjutsu.
As from what he could understand till now, fuinjutsu works as a solid base for juinjutsu.