This is gonna be AU in jujutsu kaisen new curses and people would be appearing and the ways techniques are used and can't forget about our mc as he traverse through this new world with the powers of a Phoenix
[ Third Person's POV]
Nanami was seen walking through a sewage system decimating the once human creatures, putting them out of their misery.
Nanami lessens his tie while being surrounded by corpses and says "You can come out now. I can feel your grotesque curse energy, and make it quick as horrible as they are to look like murdering people is not what I like doing as a job"
"Oh mannn, I'm both glad and disappointed to see you. Glad because killing you and experimenting on you is going to be easy. And disappointed since you're too weak to pose a challenge and get me any results" Mahito said while clapping his hands
Nanami sighs and rubs the back of his neck and looks at Mahito with a vein protruding out of his forehead.
"Let's make this quick the last thing I want to do is work on over time"
Mahito just smirked before running towards Nanami while wrapping his hand in curse energy.
Nanami seeing this also started running towards his direction which made them clash in the middle. Mahito tried to touch mahito but Nanami moved to the side and swung his blunt blade at Mahito's elbow causing it to bend in the other direction.
Before Nanami could do anything else Mahito's elbow fixed itself back up and ended up elbowing Nanami in the stomach causing his to slide back.
Nanami winced slightly and held his stomach as he slid, when he stopped he ran towards Mahito again.
When Nanami got close he swung his blunt blade again but instantly aimed for Mahito, who simply jumped out of the way. Nanami followed it up by slashing upwards but when he did Mahito used that as an opening and slipped inside Nanami's defense.
Nanami tried to back away, which he was only slightly successful at doing. Mahito managed to graze him. Which caused his side to start bleeding out of nowhere.
But Nanami didn't let that bother him, he went and got closer on his own volition even after seeing what Mahito did after making contact with him.
He swung his blade overhead trying to bash Mahito's head with it but Mahito blocked it by crossing his arms which gave Nanami the chance to use his technique making his arms a weak point and making it snap to the point his bones were sticking out breaking Mahito's skin.
Mahito, seeing this smirked before jumping back, he started waving his broken arm like nothing happened "I managed to use curse energy to block that technique, right? So is it one of those?"
"One of those? Speak Clearly I don't have time to try and guess what you mean like this is some sort of game" Nanami said using this time to study his enemy.
"I'm glad… that means you aren't opposed to talking then" Mahito said with a smirk
"It depends who I'm talking with." Nanami replied, narrowing his eyes.
'A curse spirit that can hold a proper conversation and one that has this large amount of curse energy.
I guess it wouldn't be off to say he's related to the curse that Gojo and Ash both reported about.' Nanami thought to himself without taking his eyes off Mahito.
Mahito, who was playing with his dangling injured arm, started to then speak "Hey, quick question. Between the body and soul, which one do you believe came first.
It's one of those that doesn't have a definite answer. Like the debate about what came first, the chicken or the egg. Does the soul dwell on the body? Or does the body attach its flesh to the soul?"
Nanami wanted to click his tongue not really having a choice but to listen to his random squabble "The former" he replied.
"Wrong! It's the latter" He playfully said and started fixing his broken hands "The soul comes before the body, the body tightly conforms to the shape of the soul"
Mahito then reaches into his robe and pulls out a couple of weird looking small objects.
"this isn't healing, just so you're aware. I'm just consciously preserving the shape of my soul. You get it already, right? My technique touches the soul and changes their form."
Nanami, hearing this, just checked his watch, "it's 6:30 pm, and I have been working since 11am today. So whatever it takes I will get off work at 7 pm"
Mahito then started using his curse technique idle mutation and started turning the weird objects into curses and made them start attacking Nanami.
Mahito then changed his arms into a sword and started running towards him. Nanami didn't sit still either. He started running and started using his technique on some of the corpses, Mahito then quickly appeared and tried using his sword hands and swung it towards Nanami, who blocked the attack with the blunt knife.
The curse corpses tried to then attack but Nanami used their bodies as foot holds, he pushed Mahito back and jump on a curse corpses and jumped off it gaining momentum and swinging his blunt knife with force making Mahito have to block it with two of his sword hands.
When the curse corpses started to surround them Nanami kicked Mahito in the torso causing him to go sliding back with his arms crossed. As he did he swung his blade and cut the curse corpses killing them easily.
Mahito then appeared and swung his sword hand causing a large slash to appear on his torso.
Mahito swung his other sword arm and made a cross on Nanami's chest. Nanami lowered his body due to the pain but not wanting to waste any movement used that chance and moved under Mahito's arm he swung his blunt knife on Mahito's torso sending him flying and crashing into the sewage walls causing them to crack slightly.
Even though he was injured Nanami didn't stop, he kept swinging his blade killing more corpses and when he killed the last one Mahito appeared again.
He swung his hand into a large hammer and swung his towards Nanami's back sending him flying and crashing towards the opposite wall of where Mahito landed.
Nanami was wet from the sewage water and laid on the wall with his back on the walls slightly and slowly started to get up after a while holding his side while taking deep breaths.
Mahito then reached into his robe and took out two more compressed curse corpses and shot them towards Nanami. As they were flying towards his direction they changed shape mid flight. Making it difficult for Nanami to dodge.
He ducked under the on the turned really long and smashed itself right onto the wall and used the body of the long to dodge the second one that turned wide.
He climbed on the long corpses and made some distance between him and Mahito, which he used to gather his breathing and reinforce his body and blunt knife with curse energy.
Nanami started to then loosen the tie even further and let out a reluctant sigh "Guess I'll have to work some over time"
He took off the tie and wrapped it around the hand that wasn't holding his blunt weapon and got into a fighting position while ignoring his injuries as if they didn't even matter.
Mahito was seen sitting down on a few pipes from the sewage leisurely swinging his feet "So this is how a first grade sorcerer fights… I'm starting to like this" Mahito said without his playful smile leaving his face.