Into the Hunter x Hunter world with Jujutsu Kaisen System

The place Satoru was supposed to get Ryomen Sukuna's finger turned out to be an abandoned hospital. 

Looking at the haunted look of the hospital, Sachiko nodded, "Hmm, this place looks perfect for a horror movie." 

Satoru was amused by her lack of concern about the potentially dangerous location, "Right? What about we record us walking through the halls of this creepy hospital and post it on the internet? We'll get a lot of likes!"

"That's a good idea! I can make a lot of money with that.." Sachiko hummed, entertained by the idea of it.

"You like money that much?" Satoru jokingly asked.

"Who doesn't like money? You can buy so much stuff with it.." Sachiko replied. 

"I guess.." Satoru said, "But maybe there're things money can't buy."

"Like what?" 

"Like.." Satoru paused for a while, then with a playful smirk, he replied, "A cute girlfriend." 

"What?" Sachiko took a double look at him, "I'm pretty sure you can rent one?"

"Probably not the same." Satoru laughed, "Well, not like I'd know. Seeing how I'm not even looking for one." 

"..then why would you even say that?" Sachiko asked with a sigh.

"I dunno, I just wanted to see your reaction I guess." Satoru replied with a shrug. 

"What? Do I look like entertainment to you?" Sachiko asked with a pout.

Satoru laughed and cupped her cheeks, "No, but you're pretty amusing." 

Sachiko rolled her eyes at that. 

"Well, enough talking. Let's go inside." Satoru said. 

With a nod, Sachiko followed him into the hospital.

Soon, Sachiko found herself in a big hall of the hospital. She didn't know which room it was supposed to be but there were multiple doors in the room, leading to a few smaller rooms. 

"Oh, I almost forgot. The seal of Sukuna's finger is about to be broken so there might be a flood of curses soon." Satoru said. Despite his casual tone, Sachiko could sense something was wrong with the way he was saying. 

It was as if...he was warning her.

"Satoru, what-"

"Sorry, sugar." Satoru said with an apologetic look, "I was supposed to be gauge your threat level in case you turn into a curse user. So, I have to see you fight." 

"So, you set this whole thing up?" Sachiko asked but before she could even finish, Satoru had already set up a veil, trapping her in that building as he teleported outside. 

"Fu*king bastard.." Sachiko swore as she saw the cursed energy spike soon after the appearance of the veil. How could she have fallen for such trick? She should've known better, why did she have to spend time with him of all people? Maybe if she didn't care about him or enjoyed his company, she wouldn't have ended up in this situation. 

Sachiko felt a little hurt, and angry at the betrayal but then realized that Satoru had never even stated anything about being actually into her or not wanting to harm her. Maybe she was the one being stupid. 

As numerous curses appeared one after another, Sachiko had to stop her self-blaming and fight the curses. At first, Sachiko fought normally and used her cursed energy manipulation to exorcize them. But, soon enough, she noticed that with the increasing number of curses non-stop, she would run out of cursed energy first if she kept this approach.

While she also had a newly developed nen ability and quite an impressive aura pool, unfortunately, curses could only be killed with cursed energy. If she couldn't kill the curses permanently, it was pointless to keep hitting them.  With theit sheer number, she couldn't just keep knocking them down with nen. She needed cursed energy to finish them off. 

So, Sachiko decided to use a mix of nen to strengthen her body and speed, then only used cursed energy to finish the curses off. 

The new approach was fairly efficient. It took only a few minutes to exorcize more than fifty low-level curses and a few more minutes to kill ten grade 2 curses. 

However, Sachiko realized that it was far from enough. The cursed energy emanating from the cursed object was just too much and she could see more curses coming for it. 

"I have to find the cursed object first.." Sachiko muttered. She tried her best to save as much cursed energy as she could while fighting the curses in her way and worked on finding the damn finger. 

It took longer than she expected and by the time she found the room where the cursed object was put in, almost half of her cursed energy was already gone. 

"I really do need more cursed energy, huh.." Sachiko shook her head. She needed another approach. 

At first, she didn't want to take out the cursed tool as she knew Gojo Satoru would be watching her and she didn't want to answer his questions. But, that was better than potentially never going out of here alive. 

So, Sachiko took out the Special Grade cursed tool, Scythe from the Inventory. With this, she didn't have to worry about not having enough cursed energy to finish the curses off. And to enhance her body, she could use nen. 

With a new pattern, Sachiko took down more than a hundred curses. After a while, Sachiko felt numb to the sheer number of the curses and just obliterated them. Perhaps because she was using a special grade tool, exorcizing the curses felt much easier. 

Until another curse appeared. 

It had a confusing cursed technique and by the time Sachiko realized what was wrong, she had already lost her left arm. 

Sachiko winced at the pain as this was the first time she lost a limb. Despite the pain resistance she had, it was still a significant pain. She couldn't imagine how much it would've hurt without the pain resistance and she didn't want to.

With pain resistance, Sachiko could endure the pain, and maintain a cool head to use Reverse Cursed technique to try and heal her severed arm. 

Fortunately, she had been practicing Reverse Cursed Technique a lot these days that restoring her arm wasn't impossible for her anymore. After a while, her left arm was restored. 

Still, it took more than half of the cursed energy she had left and it was starting to turn into a battle of endurance. 

Sachiko tried to be as efficient with her cursed energy as she could but it was hard to do so when she kept getting injured every now and then. 

Soon, Sachiko had to compromise by not healing her non-fatal wounds anymore and just using pain killer to stop the bleeding temporarily. As it used up less cursed energy, she could save more cursed energy to heal herself from fatal injuries. 

It briefly crossed her mind that she could upgrade her cursed energy reserves but when she checked her current curse points, she saw that they weren't being updated.

[System notification : Due to the energy disturbance in the area, System cannot calculate the curse points host has earned in a short period of time. Please wait until the issue is resolved.] 

It was the first time System was acting up like this and Sachiko got really worried at that since she wouldn't be able to upgrade her cursed energy reserves until System became normal again. 

Sachiko tried her best to push through and rely on nen by using the nen techniques like Ko and Ken the most. She also used nen to enhance her body and speed, instead of using cursed energy. But, still, her cursed energy was running out slowly. 

While she could keep fighting without cursed energy because of nen and her cursed tool, she would be out of ways to heal herself and nullify the dangerous cursed techniques. And, that would significantly raise the stakes. 

And, as she expected, after an hour later, she had completely ran out of cursed energy. The system glitch was also still there so Sachiko truly had to fight with nen and her cursed tool. 

She managed another half an hour before she lost her right arm this time and she had to use her nen ability, Sticky Steel Threads, to stop the bleeding by tying it around the injury. 

She had to hold the Scythe with her left hands and since she wasn't ambidextral person, her combat effectiveness had lowered even more. 

But, she finally managed to take down the one final Grade 1 curse after a while. As relief washed over her, she saw a figure rushing inside.

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

"Sachiko!" 

Gojo rushed inside the building as soon as he actually realized Sachiko could actually die. The curses hoard were much stronger than he had expected and he realized there was no way anyone lower than Special Grade strength would actually stand a chance. 

Using Six Eyes, he pinpointed her exact location and headed straight to there but once he was at the door, he realized that there was another barrier trapping her. It wasn't his, as he never intended to lock her in that room with the cursed object and let her die. He just wanted to see her in action so he set up a funny kind of prank where he could just bat in and save her if things actually went wrong. And, he did come to save her but he never expected that there would be this second barrier out of nowhere. 

It seemed that the second barrier also concealed him from her. Gojo noticed that Sachiko was struggling alone and pushing through to save herself. He had also seen her losing an arm and found himself sigh in relief when she managed to use Reverse Cursed Technique. 

However, his relief was cut short when he failed to destroy the barrier after a few more minutes and the situation inside started to become worse. He had to watch as Sachiko fought for her life and having to stop healing her wounds. Then, he saw her right arm getting cut off and this time, he knew she couldn't heal from that. With his Six Eyes, he could see that she had ran out of cursed energy. 

But, at the same time, she seemed to be using other source of energy to continue her fight. He watched as Sachiko used special threads to tie around her injury to stop the bleeding and he felt an ache in his chest when he saw the scene. 

He really wanted to rush in and pull her into his arms, saying it was all going to be okay now. But, the barrier wasn't budging, even after using all his power. 

Then, as she defeated the final curse, he saw the barrier disappear. 

So, he rushed in as the barrier disappeared.

"Sachiko..." 

He checked her injuries and when he saw the extent of the injuries, his hands shook a little. 

She had lost her right arm, and two of her left hand's fingers, then, she had bite marks on her shoulders, open wounds on her chest and stomach. There were also deep scratches on her thighs.

Satoru couldn't even imagine how much pain she would've been in this whole time. 

"God, sugar..." He muttered. He attempted to help her stop the bleeding as a few of the wounds she had stopped the bleeding had been starting to open up again. 

He couldn't use reverse cursed technique to heal her, he wished he could but he was helpess against her injuries. 

"I could call Shoko. No, I'll call her, alright?" He said, attempting to make amends albeit quite poorly. 

He quickly took out his phone and called Shoko. Even though he knew she was in Tokyo, Shoko was the best hope to save her.

"What do you want, Gojo?" Shoko's annoyed voice came through the speaker.

"Where're you right now? I need to come and pick you up to heal someone." He said.

"Come and pick me up? What're you.."

"There's no time. Where're you?" He asked again.

Shoko sighed on the other end of the phone before replying, "In my office." 

"I'll be there in a sec." He said before hanging up. He made sure there was no other curse or person nearby before saying to Sachiko, "Wait here a bit, okay? I'll...I'll go and grab someone who can heal you..I'll be back."

Sachiko was quite out of it when she nodded. Satoru took it as the cue to leave and he teleported himself straight to Tokyo. It wasn't easy even for him and there were a lot of restrictions for it but seeing Sachiko in that state, he just couldn't leave her be.

Soon, he reappeared near Sachiko, this time with Shoko by his side. 

"That's the person you want me to heal?" Shoko asked, no, stated.

"Yeah, you need to save her." He replied. 

Shoko sighed, then turned towards Sachiko, "I'll try my best, okay?"

Again, Sachiko just nodded. She felt fine oddly, despite the extent of her injuries and slight exhauation from running out of cursed energy and fighting for a long period of time. 

As Shoko used her Reverse Cursed Technique, the wounds on Sachiko's body started to close up and her face started to regain color. But, her right arm showed no sign of growing back.

"That's as far as I can do." Shoko said when she finally stopped her Reverse Cursed Technique. "The situation with your right arm is a little difficult. It wasn't just severed, it was as if it was cursed before getting it severed. Unless you can find someone who can nullify cursed techniques and effects, I'm afraid it'd be impossible to restore it." 

"I see.." Gojo replied. This wasn't how he wanted this night to end. If he knew, he wouldn't have set up the stupid prank in the first place. 

"That isn't a problem." Sachiko said, she was about to say she knew how to heal it given enough time but stopped herself at the last minute. 

Gojo looked at her and waited for her continuation, which never came.

Shoko noticed the change in the atmosphere so she didn't say anything more. She just asked where she was now and how to get back to a train station before leaving him alone with Sachiko. 

After Shoko left, Gojo turned to Sachiko, clearly wanting to talk. 

"Sugar, I..."

Remembering how the events went down, Sachiko didn't really want to talk to him much. She felt stupid for trusting him and ending up like this as a result and she found it unacceptable that he was talking to her as if he hadn't almost killed her just earlier. 

"Sachiko.." Gojo called out her name again when she didn't respond. 

"Are you entertained now?" She found herself asking, "You said I was amusing. So, how was the show? Did you have fun watching me fight for my life?" 

"..Sugar, it's not like that." Satoru started but was cut off by Sachiko.

"I'd appreciate if you stop calling me that," Sachiko said, "Gojo san." 

Satoru's eyes widened a bit before his face fell at the sudden formality from Sachiko and what it meant. "Sachiko...I.."

"Forget about what I said this morning," Sachiko continued, "I don't think there's anything to figure out. Because there'll be no us. There has never been. Isn't it so, Gojo san?"

"Sachiko, wait, it wasn't like that." Satoru wanted to grab her hand but realized that from his side, he could no longer hold her right hand, as Sachiko had lost it earlier in the battle because of a stupid prank he wanted to set up. 

"I didn't mean for all of this to happen..It was supposed to be a joke.." He said. He wanted to explain everything, how he really just meant it as a joke at the start and how he was prepared to rush in to save her if things go wrong and tell her about the second barrier. He didn't mean for all of this to happen. It was never his intention to make her get hurt and watch in amusement. He really wanted to, explain but he didn't know where to start. He never did, he never was a good communicator when it came to feelings and deep conversations. He was so used to not revealing his intentions and how he cared for people. He was...

"Except it wasn't funny." Sachiko laughed a little, "I was an idiot for believing you and thinking you might actually care about me even a little.. What a joke..."

"Sachiko..." But, I care about you, Satoru wanted to say but those exact words didn't come out. 

"Goodbye, Satoru." Sachiko said before turning around to leave. 

Not wanting Sachiko to leave like that, Satoru grabbed her hand, careful to not actually hurt her. 

"Wait," He said, "I know you're mad. Hell, it'd be strange if you aren't but...let's talk later. It can be way later if you don't want to talk to me right now. Just talk to me."

"No promises." Sachiko replied just before she left. 

As he watched Sachiko walk out, Satoru felt a hollow pit form in his stomach. He sank slowly onto the floor stained with her blood, his eyes fixed on the empty hallway. The usual ease in his demeanor was replaced by a rare, pensive stillness.

"Messed up this time, Satoru," he whispered to the silence of the room,"Thought I was playing it smart... just a little test of strength."

He rubbed his hand across his face, dragging down with a sigh. "Wasn't supposed to go this far," he continued, his voice barely audible. "Wasn't supposed to drive you away."

"It was just a joke... a way to see what you'd do. But it turned into a nightmare, didn't it?" His laugh was a soft, bitter sound that faded into the quiet of the place.

"I wanted to bring you closer, see if you could stand beside me. Maybe... see if there could be something more between us." His voice trailed off, laden with a regret that seemed to age him.

With a deep breath, Satoru collected himself, his figure stiffening as he wrestled his emotions back under control. "But I guess, some jokes are just not that funny, huh?"

If he could do things all over again, he probably would've never taken her here. Then, maybe she wouldn't be gone like this before he could even figure out what exactly she was for him. 

Or maybe if he could've said the words, maybe she would've been willing to talk to him again.

For once, Gojo found himself trying to process his feelings and emotions first time in a while.

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

A/N: So, I'm not exactly happy with how the fight went and stuff in this chapter.

But, Sachiko's supposed to be able to kill Grade 1 curses easily so as u guys might guess, there's something seriously wrong back there that also affected her fighting abilities. That's why she seemed nerfed and too injured in the end, but yeah, that was the gist. And I probably messed up writing the part, idk >< 

but i figured putting it away for 3 months was enough and I wanna move on to new chapter instead of being stuck here for another month or two until I suddenly get an idea on how to fix it so yeah :(

Also, I'm unfortunately still not dead so you guys will be seeing more updates of this book for sure, just not sure about the exact time. 

Anyways, we'll be back to HxH world soon.