Into the Hunter x Hunter world with Jujutsu Kaisen System

After watching Killua went to meditate, Sachiko went back to the garden to train a bit more. This time, she used 'Ren', 'Ten', 'Zetsu', 'Hatsu' and 'Gyo' at the same time to create 'Ko'. First, she used 'Ren' to increase the amount of aura surrounding her body, then used 'Gyo' to focus on her fist and 'Zetsu' to close aura nodes on other parts of the body and 'Ten' to contain all that aura in the fist.

Ko!

Sachiko tried punching a tree lightly but the moment her fist touched the trunk, it exploded and the pieces of the trunk flew all over the garden.

"So, this is the power of Ko!"

Sachiko was pleased with the results and continued practicing it until she could use it in a second. Of course, she didn't try punching anything else again as she didn't want to destroy her own garden.

After all, she paid 800 million jenny to buy this house.

She trained 'Ko' for a few more hours before going back to 'Ken'. She maintained 'Ken' even when she ate, train sword skills and rest. Because she had also trained 'Ko' for a few hours, she was tired after maintaining it for eleven hours.

Nevertheless, Sachiko was happy with the results.

Now, she could use basic techniques and 'Gyo', 'Ken' and 'Ko' from advanced techniques.

Before sleeping, Sachiko trained her Hatsu and Time Manipulation Eyes a bit more and soon drifted into sleep.

Training continuously for days was really tiring for her but the thought of becoming stronger excited her.

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The next day, Sachiko checked on Killua's progress on meditation and Killua just told her that nothing really happened yet although he was starting to sense aura.

Gon looked confused at that so Sachiko just told him to focus on getting better first before learning Nen, which the kid reluctantly agreed.

'Well, no one told him to be so stubborn and get injured so much in a spar. It's on him and Killua shouldn't bear the consequences from his actions.' Sachiko thought. It didn't make sense for Killua to postpone his training just because Gon got himself injured and she wasn't going to allow it even if she had to manipulate Killua a bit. Not that she had to worry much as Killua now wanted to get stronger himself and not too reliant on Gon.

"Alright, Killua. Focus on meditating for now and Gon, don't pout. You'll be able to train plenty after you recover. Until then, no you aren't training anything." Sachiko told the two boys.

"But,...Sachiko san, I want to get stronger quickly so that I can punch Hisoka in the face and give his badge back." Gon complained.

"Yeah, I know that but your actions have consequences. You injured yourself in a spar for being too stubborn even when you know you clearly can't win. Being determined is good and all but sometimes, that will put you in an unfavorable position." Sachiko told him, despite knowing the boy wouldn't listen to her anyway. Well, if he refused to listen, then it's on him.

Gon pouted a bit more and even sulked but Sachiko shrugged, having said her piece.

"Now I'm heading to Heavens Arena to make some more money. Bye!"

She waved Killua and him goodbye before heading to Heavens Arena. She had been training diligently for days so she definitely deserved a break, and she had decided to beat up some guys at the arena, then play with the Newbie Hunters on 200th floor.

She maintained 'Ten' on the way as usual but as soon as she was close to Heavens Arena, she stopped 'Ten' and pretended like a non-user. Her control over her own aura and aura nodes was much better and natural so it wasn't particularly hard.

She headed to 60th floor and registered, then waited until the match to beat up some random guy. This time, she controlled her strength so that her opponents wouldn't die.

She repeated the process till she got to 100th floor. She wasn't placing a bet for these floors as she didn't want too much attention by placing bets for herself. Besides, she had ended up killing the two guys she fought so if she was in the spotlight, she'd get less money from bets. So, she was planning something else.

"Alright, now time for next part of the plan!"

The next part was simple, she would take a few more moves before defeating her opponents to give the illusion that she wasn't that strong. That way, she would get a lot more money from bets and as she was also pretending to be a non-user, she'd be able to play with the Newbie hunters when she gets to the 200th floor.

With a plan in mind, Sachiko headed home first. She would ask Killua to place bets when she fought on 100th floor after a few days.

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In the mean time, Sachiko practiced 'Ko', 'Ken' and 'Hatsu' and when she was taking a rest, she'd maintain 'Ten'. She still couldn't maintain it in her sleep but she wasn't in a hurry to do that.

Three more days passed since she got to 100th floor and Killua had also started opening some of the aura nodes. Gon had also healed almost completely but Sachiko told him to wait a few more days before getting back to training.

Killua felt a bit bad for leaving Gon behind but he wasn't really willing to pause his training after Sachiko told him that he was close to opening all his aura nodes. He was so close to finally wield the power his whole family had this whole time. He wasn't going to fall behind now.

So, on the sixth day of his meditation, Killua successfully opened all of his aura nodes.

"Congragulations, seems like you succeeded!" Sachiko told him.

"I succeeded. Now what do I do?"

"Well, let's start with 'Ten' first. Now 'Ten' is a basic used to keep all that aura from leaking and provide some protection against Nen attacks." She explained the concept to him and gave him some time to try it out.

Needless to say, Killua successfully used 'Ten' in a few minutes.

"Great! Now, try to practice that as much as you can for a few days. Then, you can register at Heavens Arena." Sachiko said cheerfully.

"Okay. But will this be enough for 200th floor? You said everyone's a nen user up there and I just learned a basic technique." Killua asked.

"Don't worry. I'll teach you more about Nen while you're climbing up to 200th floor so you'll be fine as long as you actually practice." Sachiko said confidently.

Killua nodded eventually, "Alright, I guess I'll focus on Ten for two days before going to Heavens Arena."

"Alright, I'll go find Gon to introduce him to Nen. I bet he's dying to learn it." Sachiko said with a chuckle.

"You bet, he's complaining and pouting all day earlier this week." Killua said with a sigh. "Couldn't you have done something to speed up his recovery and teach him Nen faster?"

"I don't know but it's not my fault that he got injured. I told him to stop but he didn't listen!"

"Well, I guess that's true. Anyway, good luck teaching Gon after making him wait almost a whole week." Killua stuck his tongue out before running away.

"Seriously..."

Sachiko sighed as she headed to find Gon. Then, she basically repeated the explanation she gave to Killua and guided him to open his aura nodes by meditation. As Killua said, Gon was very eager to learn.

After leaving Gon to meditate, it was already evening so Sachiko decided to take a break and soon, she quickly fell asleep.

In the middle of the night, she woke up with a System reminder.

[Reminder: Host has not been in Jujutsu Kaisen world for 21 days. Issuing a mission: Go to Jujutsu Kaisen world in 24 hours to finish the fight with Geto Suguru. It is recommended to not be away from Jujutsu Kaisen world for more than two weeks in the future.]

"Fight with Geto Suguru..." Sachiko muttered quietly. "Seems like I can't really postpone it anymore."

Sachiko initially wanted to wait until she learned all of the advanced nen techniques before facing Geto again but with the System Reminder just now, she felt that there were limits to her freedom when it comes to crossing worlds.

Because there wasn't a rule like that until she took advantage of the ability to cross worlds and time stopping during that time.

But, first, she decided to focus on continuing the fight with Geto Suguru. She tried analyzing her abilities and the progress in the past twenty one days.

She enhanced her physical strength by twenty times that of the average strength of Killua and other three and even her reflexes through System Store. She also upgraded her cursed energy manipulation technique to Proficient and her sword skills to Competent. Not to mention she also learned Nen and mastered Zetsu, Ten, Ken and Gyo.

So, Sachiko felt that she wasn't as helpless as before.

However, preparations still have to be done.

"Developing my Hatsu in the direction of a Transmuter could be the game changer in the battle with Geto Suguru but 24 hours isn't enough time to develop a Hatsu to use in the battle." Sachiko thought for a while. "Seems like I can only go with other advanced nen techniques."

With that in mind, Sachiko headed to her usual training place to practice Ko again.

Of course, she didn't actually lunch anything using it but she practiced gathering and focusing the aura in her fist or other parts of her body.

After a few hours of training, she upgraded the mastery of it to Competent.

She then took a break before going back to training. This time, she tried to use 'Ryu'.

It took some time to get it right and even more time to switch the concentration of aura between different body parts. By the time, she got Ryu to advanced beginner, the sun was already high in the sky.

Sachiko realized it was already two pm after checking the time. So, she had to take a break, have some lunch before she went back to training.

She stopped the training in the evening to sleep for a while before heading to Jujutsu Kaisen world. By that time, she was still at advanced beginner in Ryu and Competent in Ko but she felt like she could manage.

So, after a nap, Sachiko changed into the same outfit she was wearing during her fight with Geto Suguru and it was even in the same dirty state.

"With all these done, let's finish this up."

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Sachiko chan's update stats

Name : Nakamura Sachiko

Alias : None.

Age : 19

Relationships : Gon Freecs (Close Friend), Killua Zoldyck (Adopted brother), Kurapika (Friend), Leorio (Friend), Hisoka (Rivals), Illumi (Enemy), Geto Suguru (Enemy), Gojo Satoru (Acquaintance ), Wing (Acquaintance).

Assets : 225 million yen, 800 million jenny house, 101,350,000 jenny.

Hunter level : C

Jujutsu sorcerer level : Grade-1

Cursed technique : Cursed energy manipulation (Proficient), Time Manipulation Eyes (Advanced beginner), Nullify (Novice), Pain killer (Competent), Reverse Cursed Technique (Advanced Beginner).

Cursed energy : 9400/10,000

Cursed energy reserves rank : C

Nen Techniques: Ten (Proficient), Ren/Ken (Competent), Zetsu (Proficient), Gyo (Proficient), Ko (Competent), Ryu (Advanced Beginner).

Nen Abilities: None.

Nen Type: Manipulator, Transmuter.

Aura pool: 82,000 units

Curse points : 280.

Hunter points : 20.

Cursed tools : Special Grade Scythe.

Skills : Intermediate Sword Skill (Competent), Assassins Art: Shroud (Competent), Assassins Art : Silent gaits, Rhythm Echo (Competent), Disguise (Novice).

Abilities : Enhanced sense : Eyesight , Super Hearing, Superior Strength (20x), Enhanced Reflexes.