{Flashback to 1 year ago. Geto and Jin during on of their training sessions.}
"So, this is how you use a simple domain? It seems easy enough."
Jin stood in the middle of a blue circle with his hands clasped, channeling a simple domain. Since he lacked a domain expansion, Geto had offered to teach him anti-domain techniques instead so that he would be able to survive against sorcerers that do.
"Heh, I'm glad you think so. You'll need it whenever you fight Satoru. By now, he should've already mastered his domain expansion. Sigh. You know..."
Jin continuously used his simple domain as he listened to Geto's words. As a nuclear energy manipulator, he had a different understanding of energy manipulation in general compared to other sorcerers.
Especially since so many different forces were behind nuclear energy. It was immensely difficult to even figure out how to access those energies in the first place.
So compared to that, opening and maintaining something so "simple" as a simple domain was child's play.
"Why do you want to defeat Satoru so much? He doesn't need to be defeated for the plan to work, just distracted. Miguel is good enough for that. Its almost like an obsession."
Jin smirked as he responded,"An obsession huh? I guess if you put it like that, it might not be too far from the truth. There are a few reasons that I want to go against him. One, he is the only one that can withstand my full power. I improve exponentially with every minute we stay in combat. Two, I have to defeat him, simple as that. Three..."
Geto raised an eyebrow as Jin released his simple domain and caused what seemed to be a green orb crackling with lightning to appear over his fist.
"I want the Six Eyes. It would take my sorcery to new heights. With my new technique, even a domain wouldn't be able to stop me."
{Back to current day.}
The moment found himself encased in darkness, he knew that he had milliseconds, if not nanoseconds, to react.
He immediately opened his simple domain as the darkness became littered with stars and what seemed to be a singularity in the background.
"Simple domain huh? I see you've been practicing. But...how long can you survive within?"
Gojo was right. Against a powerful domain expansion like Unlimited Void, simple domain could only last for a few seconds at most. Even though Jin was a highly proficient user of it, Gojo's domain was just too overwhelming.
But that time was all he needed.
Seeing his simple domain visibly shredding away in front of him, Jin quickly formed a hand sign and adjusted his stance to a lower position.
"I'm curious, Gojo. Can you survive against my this? Or will your sure-hit strike me before I can even manage to do it? Heh...this is the kind of fight that gets my blood pumping."
Green energy appeared over Jin's fist accompanied with a similarly colored aura that didn't even slightly resemble anything he showed thus far.
'Hm? That energy...?! If I'm correct, that's...!'
Over the years after their fight, Gojo didn't just spend all of his time twiddling his thumbs when it came to studying Jin.
After his first experience with him, he went to great lengths to study nuclear power and other forces related to it. Especially the more dangerous aspects of it, like the radiation that had caused the area around the Time Vessel Association to be off limits for years.
'And if I'm right, that kind of radiation is...!'
To be able to charge this technique and concentrate on maintaining his simple domain in the face of such overwhelming power was a testament of Jin's skill in sorcery.
And all of that effort he put in over the years was about to pay off.
"Try to survive, Gojo."
Jin suddenly punched the ground beneath him with all off his might, disengaging the simple domain as he did so.
'Maximum Technique: Gamma Burst.'
BOOOMMMMM!!!
Of course, the moment he stopped his simple domain, Gojo's sure-hit technique struck him right away, but it only lasted for less that a tenth of a second before Gojo's domain erupted with a ever-expanding pillar of green light that destroyed it immediately.
Both Jin and Gojo were sent flying as the as the gamma rays spread throughout the city, ionizing and vaporizing everything in its path.
Any sorcerer or cursed spirit unlucky enough to be caught in the blast radius met the same fate. Only the strongest could withstand the destructive power of the attack.
It didn't help that the attack wasn't just a full burst of gamma radiation, other forms of destructive energy existed within. Quantum energy being one of the especially dangerous few.
The sky over the city became illuminated in a dark shade of green that added an extra layer of despair upon any survivors unlucky enough to not die from the initial blast.
The radiation just continuously destroyed their cells instead or the remaining energy fell from the sky like rain, finishing off those below.
The scene was absolutely harrowing. Even the blood from those vaporized didn't remain.
Now, they only existed in memory.
There were only two words that could describe Jin's Maximum Technique in this moment.
Destruction Incarnate.
In a pile of mostly vaporized rubble not far from the initial explosion lay the culprit, Jin.
His mind and body stunned into paralysis by Gojo's sure hit technique within the domain.
His prefrontal cortex burned out from the overuse of his cursed technique.
Right now, Jin was in the most precarious position he had ever been in since arriving in this world.
The closest to death.
But, he was still concious.
'My mind was overloaded was so much information in that slight timeframe that it's hard to even move. If i didn't prepare for this fight...heh. I can't say it enough. Gojo Satoru is a monster.'
Eyes still open but unable to move, Jin looked as much as he could at the aftermath of his technique.
'So much destruction...if I had this power before I was sealed, I would have been unstoppable. That reminds me...what about that ring I found just before I was sealed? Is it still where I left it?'
Now unable to move, Jin's thoughts just went off into random directions as he struggled to gain control over the massive amount of information that just entered his mind.
On the other hand, Gojo lay about 200 meters away from Jin in a similar pile of rubble, blood running from every conceiveable orifice on his body.
His breath haggard.
His eyes bloodshot.
His body on the constant brink of radioactive decay.
Gojo's RCT was working overtime to combat the influx of Gamma radiation assaulting his very DNA.
'I...assumed he could only bypass my infinity with close range attacks. But who would've thought that he would use Gamma radiation? If i knew this...I would've just come to Shinjuku myself. So many sorcerers died from that attack...I couldn't save anyone. Jin Itadori...I can't let you stay on this earth for one more day. You're a monster through and through!'
No matter how much Gojo tried to get up, his body wouldn't listen to him.
"Tch! Move!"
Nothing happened. Gojo could only lay there and lick his wounds as he tried to survive the overbearing power of Gamma radiation.
Effectively, both Jin and Gojo were on deaths door. If anyone with ill intentions were to attack them now, it would be over.
The strongest sorcerers would be taken out just like that.
Fortunately, anything living within a five kilometer radius was vaporized.
This state lasted for about an hour before one of them finally regained some sort of motor function.
And as one would've guessed, it was Jin.
As he had laid on the ground, unable to access his cursed technique, he dedicated his focus to one thing, Reverse Cursed Technique.
Turning the negative aspect of cursed energy into a positive.
Behind achieving Domain Expansion, RCT was another obstacle in his way of achieving complete mastery over sorcery.
While he had achieved the technique over the years, there was never a time where he had to use the technique as he had better ways of healing via his own cursed technique.
Now, he had no choice.
Jin stood up and started slowly walking towards where he sensed Gojo as he healed his prefrontal cortex.
'It's time to take what I really came here for. And in return...'
Jin looked at his palms and sighed. To sacrifice something so powerful made his heart tinge with pain.
But the Six Eyes were too much to pass up on.
The moment he healed his prefrontal cortex, Jin stopped channeling RCT and appeared over at Gojo's location in a flash.
Of course, the latter was still laying there, fighting off the radiation.
The two looked at each other as Jin approached.
"I spent years working on that technique just for you, Gojo. Seeing you unable to counter it makes my heart jump with joy."
Gojo, still processing the death of so many of his colleagues, wasn't in the mood for any quips or jokes.
"I'll kill you. Even if you manage to kill me now, I'll crawl back from the jaws of death and finish you off like the dog you are."
Jin threw his head back in laughter.
"It would be nice to kill you here and now, but I've come for something that requires you to live."
Jin stepped forward, grabbed his face and slammed him down on the ground, causing fissures to run through it.
"I wonder, after this is done, what will you think?"