Into the Hunter x Hunter world with Jujutsu Kaisen System

The first thought that came to Sachiko's mind as she looked at the mission was "What the fu*k..". While she agreed to fight Hisoka, she wasn't planning to actually fight him before she finished developing her nen abilities. It could be said that the System mission was pushing her to fight Hisoka much earlier than she would've preferred.

'I can probably skip it..or don't do it since there're no penalties mentioned. But, where's the fun in that?' Sachiko thought.

The mission was to not just fight Hisoka, but she also had to win. She had to make Hisoka lose the match with her and made him fall all the way back down from 200th floor.

Sachiko knew it wasn't going to be easy but at the same time, she didn't feel like it was impossible to win against Hisoka in Heavens Arena.

Also, it didn't hurt to just try and the reward for the mission was also quite enticing.

'Alright, I guess I'll try. Who knows, this might be a good chance to kick that clown's ass?' Sachiko thought to herself.

Then, she texted Hisoka.

"I'll fight with you exactly 90 days later."

Although a little over three months had already passed since the Hunter Exam and Sachiko agreed to meet with Kurapika and Leorio at Yorknew city, she didn't really want to rush into the fight.

Also, who cared about being a little late? Sachiko sure didn't, and potentially kicking Hisoka's ass sounded a lot more fun than the Yorknew city at the moment.

As for Hisoka potentially not agreeing to the date, Sachiko wasn't worried about that. She knew Hisoka was way too invested in fighting her and while Hisoka would probably want to fight with Chrollo more, there was no guarantee that Hisoka would get to fight Chrollo in Yorknew city at this moment. So, Sachiko was pretty optimistic.

Hisoka's reply came shortly after her message.

"90 days later's not good. I have to be at somewhere."

So, Sachiko replied, "Well, let's just cancel our match then. If you can't figure out a way after agreeing to my conditions earlier, I'm not interested anymore."

That gotta push Hisoka. Sachiko smiled as she texted back.

As Sachiko expected, Hisoka replied, "There'll be no need to cancel our match. I'll be there 90 days later to fight you."

"That's the spirit." Sachiko replied, "See you at Heavens Arena 90 days later then."

-----------------

"Oi, you kept being on your phone. Did you hear me?" Killua was complaining as Sachiko kept texting back and forth.

As she had already got what she wanted, Sachiko put the phone away and messed Killua's hair up with her hand, "Yes, yes. What do you want, my little brother?"

"Stop that, it's embarrassing!" Killua said, "And, you didn't hear what I was saying, did you? Seriously..who're you even texting with?"

Sachiko replied casually, "Oh, I was just texting Hisoka to set up our match."

"Your match? You're fighting him?"

"Well, he had been pestering me for a fight for quite a while now and he had just racked up 9 wins. Isn't this perfect time to knock him down?" Sachiko replied with a chuckle.

"Only if you win." Killua crossed his arms.

"Of course I will win." Sachiko replied, copying Killua and crossing her arms, "Who do you think I am? Have I ever got beaten before?"

Killua was unimpressed and he decided to point out, "Yeah, you have been. During Hunter Exam when we went through the Swindler's Swamp. I saw the bruises."

Sachiko gasped dramatically, "What? That didn't happen!"

"Are you seriously gaslighting me?" Killua rolled his eyes.

"Did it work?"

"Obviously no." Killua sighed.

"What a pity." Sachiko replied, "Anyways, I'm kicking his ass so come and watch if you can. Tell Gon and Wing san too."

"Why don't you say it yourself? Are you going somewhere?" Killua asked.

"Yep, I'm going on a trip. So, tell Gon to rest up and after that, give him a lecture for his recklessness ne~" Sachiko told Killua as she basically waved goodbye. She wasn't even planning on packing up for her so-called trip. Obviously when she was practically a billionaire, she could afford to buy new things on her trip so there was no need to worry about small details. That was the perk of having money!

"Are you at least telling me where you're going? Or if you're gonna be at Yorknew city as you agreed to Kurapika and Leorio?" Killua asked with a sigh.

"Nope, but I'll be there at Yorknew city, probably.  Just text me if you need anything including information. Although I might charge you depending on what you need from me." Sachiko said because hell, she didn't even know where she was going. She just wanted to go on an adventure and finish building her nen ability without the responsibility of the two kids.

"That sounds like you I guess." Killua sighed.

Sachiko laughed at Killua's reaction, "Alright, don't miss me too much."

"Like I will!" Killua retorted but as he watched Sachiko skipping away, he felt like he would deep down.

---------------

Wing sighed in relief when he saw the match finally ended and Gon wasn't that injured. He was pretty shocked to see Gon in match with Hisoka out of the blue but he brought Zushi to watch the match with him.

After the match, he went to look for Gon and met Killua who walked into the room with an annoyed look.

"Killua!" Gon waved. He then tilted his head and asked, "Did something happen?"

"Eyepatch lady left us. She said she was going a trip." Killua answered, "Seriously, she said she wasn't done teaching us and now, she just decided to go off to somewhere."

"Really? Where did she go?" Gon asked.

"No idea." Killua shook his head, "But, she told me she's fighting Hisoka here 90 days from now."

"Sachiko san is fighting Hisoka?!" Gon asked.

"Apparently." Killua replied, he then turned to Wing and said, "She also told me to tell you about the match too. She probably wants you to go and watch."

Wing nodded, "I think it'll be a good opportunity to show Zushi a few examples of nen in battles."

"In that case, I want to watch it too." Killua said, "Although I'm still not sure how I can because I have to be somewhere in the next three months."

"Yeah, we promised to Kurapika and Leorio.." Gon sighed. "I really wanted to see Sachiko san and Hisoka fight."

"In any case, we know she's gonna be here 90 days later so she didn't completely disappeared." Killua said.

"Yeah.." Gon muttered.

"What're you planning to do in the mean time?" Killua asked, "I'm thinking of fighting a few matches here before going to Yorknew city."

Gon replied, "Well, I was thinking about going back to the island for a while."

"I can come with you after a few matches. In any case, eyepatch lady is not here anyway. There's no need for me to stick around." Killua said.

"That sounds good, Killua!" Gon smiled happily at the thought of his friend coming with him.

Soon, they said goodbye to Wing and Killua decided to set up a match for the next day. After that, he would go with Gon to visit the island.

---------------

After leaving the two kids, Sachiko decided to go to Jujutsu Kaisen world first and went to a different city.

There, she rented a haunted house in a shady neighborhood where no one really wanted to live in because that worked better for her. Then, she started to obsessively practice Nullify with a few more gases and even Carbon monoxide. At first, she could only nullify small amounts and as the concenteation of the gas increased, she started to get the negative effects from it. If not for her reverse cursed technique, Sachiko knew she would've ended up at the hospital. But, everything worked out quite well so she didn't really care.

As a result, she managed to nullify Carbon monoxide fully for a few hours straight and in higher concentrations, she could nullify it to nearly an hour. Although she needed to use reverse cursed technique to heal herself from the damage done afterwards if she used any longer than an hour for higher concentrations, it also served as her training in Reverse cursed technique so Sachiko didn't stress about it.

Oh the fifth day, two days before she went back to Hunter x Hunter world, she went out for a nice dinner.

"This is quite nice." Sachiko nodded in satisfaction as she took another bite of expensive sashimi.

"Oh, isn't this Sachiko?" Sachiko heard a familiar captivating voice. As she turned around, she saw Gojo Satoru in a grayish blue shirt and black sunglasses. His blue eyes stared into her eye(s), as she turnrd around and met his gaze.

"Satoru, you're in this city too?" Sachiko was surprised to run into him here, especially because he went back to Tokyo a while ago.

"Yep," Satoru replied, "I'm not expecting to meet you here. Like what're the chances?"

"Right?" Sachiko shook her head with a laugh.

Satoru sat in front of her as if he owned the place, then asked, "You don't mind if I join you?"

"You know you're supposed to ask before sitting, right?" Sachiko asked.

Satoru grinned, "Well, I figured it couldn't hurt to sit. Or were you going to say no?"

Sachiko said playfully, "You know I could still say no."

"Alright, sorry, sorry." Satoru said without any actual remorse or making any effort to get up.

Sachiko shook her head and asked, "So, you paying?"

"I don't mind." Satoru shrugged.

"Sweet." Sachiko nodded, "I'm ordering more."

Well, Satoru didn't seem to mind. In fact, Sachiko noticed he didn't even care how much money he was going to spend or how she was treating him like a free meal ticket. So, obviously, she had to get like three desserts which was the maximum amount she could eat anyway. But, to her absolute horror, Satoru had ordered the entirety of the dessert menu with his defense being he rely on sweets to be alive.

"What? Aren't you eating your chocolate cake?" Satoru asked playfully, "Do you want me to eat it? or you can't eat because you're so distracted by my attractiveness?"

"....What're you even talking about?" Sachiko replied, her cheeks becoming a little flushed as Satoru teased her playfully. It didn't help that Satoru was actually an attractive guy and he knew what he was doing.

"Are you embarrassed? Your cheeks're red. How cute." Satoru said with a chuckle.

"S-stop it."

"Do you really want me to, cupcake?"

"Stop calling me that!" Sachiko nearly threw the water glass towards him. The only reason she stopped herself was because it was pointless. There was no way the glass would hit him with his infinity turned on.

"Alright, alright." Satoru laughed, "I'm just joking."

"Seriously.." Sachiko sighed.

Satoru went back to eating and he soon finished his desserts. "Well, this was nice. Wanna grab dinner tomorrow with me as well?"

"Sure, if you're paying." Sachiko replied because it was free food, and totally, not because she found the guy attractive. Well, maybe she did, a little, or maybe a little more than that but that was totally not the point. She was just going out for food, that was what she told herself.

"Also you gotta stop calling me your weird nicknames." She added. Sachiko didn't actually hate the names, she just didn't want to look like a tomato. But, Gojo Satoru didn't have to know that, Sachiko thought there was no need to make the guy's ego any bigger.

"Sure, I'll pay but no promises for the nicknames." Satoru replied with a laugh.