Sealing Jutsu.
In the original work Naruto, its frequency and importance are extremely high, from the earliest Eight Trigrams Sealing Style, which is two Four Symbols Seals stacked to seal the Nine-Tailed, to later defeating the final boss Ōtsutsuki Kaguya with Six Paths: Chibaku Tensei.
One could say Sealing Jutsu's status in Naruto can be ranked alongside the Sharingan, Tailed Beasts, and others. Didn't you see how Kishimoto specifically wrote the Uzumaki Clan, who were skilled in Sealing, as extinct?
Yet, for such an important system, Kishimoto only used it for plot purposes in the original work, never mentioning a single word on how to cultivate it.
Judging from the scroll Danzo gave, the so-called Sealing Jutsu is about using one's own Chakra to exploit gaps in the opponent's Chakra, or to impose certain restrictions. Then, layer by layer, shackles are applied, achieving a feeling of using the small to overcome the large.
Of course, this is the most basic concept. Later, it's also said that the vast majority of Sealing Jutsu use stronger Chakra or special techniques to forcibly suppress objects or living beings.
The simplest among them is the Summoning Scroll for Sealing ninja tools, which is also the only Sealing technique recorded on this scroll; the rest are just annotations.
[After all, ninja tools are inanimate objects and generally don't have their own Chakra.]
Tian Yin quickly unsealed the summoning ninja tool scroll she carried and arranged to begin training together with her Shadow Clone.
One night later... Poof! Poof! Poof!
Several scrolls used for summoning release opened one after another. Danzo nodded in satisfaction.
To go from zero to constructing a complete seal and achieving the effect in one night. Even with ten Shadow Clones, this is enough to prove that Uzumaki Tian Yin truly has talent.
You must know, even Danzo himself took about three days back when he learned this to achieve the level of perfection Tian Yin is showing now.
"Good. Now release your Chakra at full power for me to see."
Tian Yin obediently complied.
Looking at the deep blue Chakra swirling around Tian Yin, Danzo couldn't help but inwardly praise the Uzumaki Clan.
His surveillance began as soon as Tian Yin took the scroll last night. A full ten-person Shadow Clone training for nearly ten hours, and she's already completely recovered!
For a moment, Danzo considered whether to teach her the Multi-Shadow Clone Jutsu technique. But he quickly dismissed the thought; he still needed to shape Tian Yin further.
But this matter couldn't be rushed. Danzo had to ensure he wouldn't be detected by Hiruzen Sarutobi and needed to arrange things meticulously.
In the following period, Danzo continuously fed Tian Yin various Sealing Jutsu to learn. Once she mastered Sealing inanimate objects, they started practicing on living beings, which was indeed much more difficult because the Chakra within a living being could instinctively defend against intrusion.
If she just applied formulas like Sealing inanimate objects, she would either fail or kill the living thing.
However, although Tian Yin was only 4 years old, her Chakra could completely overpower a normal Chunin through sheer force. As long as suppression was possible, then shackles could be slowly applied afterward. This is also the mainstream approach for most practical Sealing Jutsu.
To put it simply, it's like hitting someone hard in the face, then quickly tying them up while they're still dazed.
However, functional Sealing Jutsu still must follow the basic principles. This type primarily tests one's control over Chakra, which is very similar to Medical Ninjutsu.
This gave Tian Yin some trouble, the reason being her massive Chakra made the control required for normal training difficult to keep up with. Danzo provided a solution: train in Chakra Shape Transformation.
At this moment, the first thing that came to Tian Yin's mind was the Rasengan.
This ultimate Shape Transformation, seal-less Ninjutsu developed by the Fourth Hokage, Minato Namikaze, based on the Tailed Beast Ball, is so famous in the anime world that basically anyone who transmigrates to Naruto must practice it.
But Tian Yin dared not work on this within the Root.
In this place, try practicing with lots of water balloons, solid rubber balls, and air balloons? Forget whether you could even get your hands on them, your every move is under surveillance.
The method Danzo gave was to consciously mold Chakra into various shapes like cubes, the more complex and precise, the better.
Of course, this wasn't done out of thin air; there was a reference.
In the original Naruto, Sasuke once used a Shape Transformation of Chidori Current—Chidori Senbon—against Deidara, disabling the spider-shaped clay bombs.
The first step to training to this level is to continuously channel Chakra into a senbon, then visualize this shape in your mind and maintain it. Other conventional Shape Transformations, including extremely fine Chakra threads, follow the same principle.
Training this went very smoothly for Tian Yin because, whether cultivating Chakra shape or nature, a calm mind is of paramount importance.
Tian Yin had already been in the sunless Root for 4 years, and Danzo, to erase emotions, certainly wouldn't give her much entertainment. Under these circumstances, it was hard for her mind *not* to be calm.
Coupled with the experience amplification from Shadow Clones, within a few weeks, Tian Yin's Chakra control caught up with the demands of Sealing Jutsu.
And so, the days of being instructed by Danzo in Sealing Jutsu and Chakra Shape Transformation passed one by one. During this time, Danzo also found time to test Tian Yin's Chakra nature, which were Wind, Lightning, and Water. But testing was just testing; Danzo showed no intention of teaching her any Ninjutsu.
Soon, half a year later arrived.
"Rest well tonight. Come here tomorrow, and I will conduct another assessment of you."
Still sparing with words and offering no explanation, Tian Yin was quite used to this by now.
Keep pretending, you sexy Sun-bro who stabs Susanoo with a Kunai.
While recalling Danzo's demise in the original plot, Tian Yin's mood gradually became more cheerful. This was her unique way of thinking to possibly combat depression.
Clang!
Then, encountering a not-unexpected surprise attack, Tian Yin casually pulled out a Kunai to block it.
"Long time no see, Yue."
The one who came to ambush was Yue, which made Tian Yin a bit surprised. Ever since her small victory over her half a year ago, Yue hadn't appeared before her.
As for the occasional ambushes, the number of participants had increased, but Yue's figure was never among them.
To be honest, Tian Yin missed her a little. After coming to this world, it was this big sister codenamed Yue who personally taught her how to extract Chakra, how to climb trees, and how to walk on water.
She even thoughtfully taught her some essential skills for girls, like combing hair, washing her face, and skincare. For Tian Yin, who was a boy in her previous life, this opened a brand new door.
"You seem to be in a good mood. Don't let your guard down because of it."
"What brings you here?"
"I wanted to come and chat with you."
A trace of suspicion arose in Tian Yin's heart, a feeling of something wrong, an intuitive sense of unease wrapping around her.
"Then, Yue, can you teach me a few Ninjutsu moves today? I had my Chakra nature tested a while ago."
Tian Yin acted like a child eager for cotton candy, her face adorned with a thick sense of anticipation.
"Unfortunately, learning Ninjutsu must be approved by Lord Danzo. But haven't you already been taught Sealing Jutsu? Be careful not to bite off more than you can chew."
"That's truly a shame. In that case, let's go inside to chat."
After saying this, Tian Yin proactively invited Yue into her room.
It was very simple. Besides some necessities, there were only some ninja tools. But on one wall, dense scratch marks were visible. On the desk lay a notebook, brush, ink, paper, and inkstone, all covered in writing Yue couldn't understand.
Yue couldn't help but pick up this diary. On it were letters like some kind of code, but not any Yue recognized.
"This is something I wrote for fun when I was learning codes. You know, this is one of my few pastimes."
Tian Yin couldn't tell her it was written in Pinyin. Anyway, in Naruto, there was indeed a setting where English was used as a code, so the chance of discovery was almost zero.
Moreover, what was written wasn't mindless; most were cues to remind her of important plot points in her mind.
"Not very girlish. I know two other male members whose pastime is drawing. This world is really strange."
[Drawing? Could it be Sai and his brother Shin?]
The one who debuted in shippuden popped into Tian Yin's mind—it was from him that the existence of Konoha's Root was formally revealed.
"They're called Kō and Shin. If you get the chance, you could learn drawing from them too. Especially that Kō, his skills are truly exceptional."
As she spoke, Yue unsealed a sealing scroll from her bosom. It was a simple vase with a vibrant red flower inserted.
"I definitely will if I get the chance. By the way, what's this?"
Tian Yin didn't know much about flowers, neither in her previous life nor this one.
"For you. This flower, as fiery red as your hair, consider it a memento from me before I leave. This mission I'm departing on won't be something resolved in half a year. Don't tell me you little girl won't miss me at all!"
Yue let out a light, teasing laugh, making Tian Yin involuntarily feel like teasing back.
"Haha, Sister Yue can be considered my teacher, you know. For the past half year, since starting instruction under Lord Danzo, no one here has taught me how to braid my hair anymore. How about Sister Yue teaches me some more today?"
Saying this, Tian Yin turned around. Without hesitation, Yue came to her side and began to braid the fiery red hair, guiding her hands.
The two didn't speak further. In the quiet room, only the friction of hands, comb, and hair remained.
"Say, Jiu, have you ever thought about who your parents are, why they sent you here?"
Yue suddenly asked.
"No name, no emotions, no past, no future, only the mission in my heart. I don't care who my parents are. As a Root of Konoha, my heart holds only the thought of serving Lord Danzo with all my might."
Tian Yin's reply held no hesitation, but her tone wasn't icy and hollow; instead, it was filled with a sense of Of course (naturalness).
[Testing me? I've practiced this classic line.]
"Is... that so? Is that really how you feel?"
"Isn't that how it's supposed to be? Besides, I don't really understand what parents are. Since that's the case, why should I think about this question?"
After these words, Yue's movements stopped.
Then, Yue slowly embraced Tian Yin from behind, resting her mask on Tian Yin's head and beginning to sob.
"Yue? Are you crying?"
Tian Yin asked with concern.
"It's nothing. Then, Jiu, do you want to know what parents are?"
"The people who gave birth to me. That's written in books, along with the method."
Faced with Tian Yin's blunt and simple expression, Yue seemed amused by this response, but then she said:
"Parents... they are beings who love and protect you with all their heart. Imagine me behind you now. I have the same fiery red long hair as you, looking at you gently."
After saying this, Yue waited a moment, then slowly turned Tian Yin's head around.
"Ah..."
Before Tian Yin's eyes appeared a familiar woman, but one she should act as if she didn't know.
Fiery red hair, black pupils, a round yet mature face filled with gentleness.
"Is this Sister Yue's true appearance? She looks so much like me..."
Tian Yin's eyes widened in disbelief, her small hands already unable to resist reaching up to touch the other's beautiful face.
"A bit lighter, child. You're using too much force."
Tian Yin's strength was great. This didn't seem like a curious caress but more like she wanted to pinch her face off.
"Why does Sister Yue look so much like me? Could it be... you are actually my mother?"
Tian Yin herself didn't realize that as she said this, her tone carried a chill. It was just that her tender child's voice made this less obvious.
"Hehe~ What do you think? Oh dear, child, aren't you going to let go?"
"Tell me~ Sister Yue~ I'll let go if you tell me."
"Hehe~ Then I'll tell you after you pass Lord Danzo's assessment tomorrow."
After saying this, Yue patted Tian Yin's head, got up, and left.
On the bed, Tian Yin silently watched Yue leave. She then sat for a long time before suddenly pinching the skin near her heart.
Genjutsu, Transformation Jutsu, or even direct surgical cosmetic alteration—to actually transform into Uzumaki Kushina's appearance and come say these things to her!
This Danzo being called pot hokage really isn't unjust!
Getting up from the bed and walking to the vase Yue had just given her, Tian Yin unhesitatingly sealed it into a sealing scroll.
She didn't know if the flower had any issues, but it was better to be safe than sorry. Moreover, this way of handling it gave her more room to maneuver than simply smashing it.
[I need to wash up. In the four years since coming here, I've never felt as disgusted and furious as I do today!]
This inexplicable fire in her heart almost made Tian Yin directly slap and tear that face apart just moments ago!