Mahito + Clone

"Junpei!" Itadori Yuuji screamed as he saw Junpei turn into a hideous monster.

"You bastard! What did you do? Turn him back!"

Hearing this, Mahito grinned, his eyes curving into two crescents.

"Don't want to~ It might be too late to save him, unless..."

Yuuji, running out of options, turns to the malevolent being residing inside him and asked, "Sukuna! I'll do anything you want! Just save Junpei! Use that thing you used to heal my body!"

A small slit opened on side of Yuuji's mouth, revealing two rows of teeth. The two sides of the mouth curled upwards before a voice that was full of joy sounded out.

"I refuse!"

"What?" Yuuji's eyes widened in shock.

"How amusing!" Sukuna said while chuckling, "You'd give up your pride, your everything, to try to rely on me... and you can't save anything!"

As he finished Mahito also started to chuckle, before both of them broke out into full on laughter.

Yuuji, on the other hand, felt his body tremble in anger. The sounds of laughter started to fade out of Yuuji's mind, replaced with indescribable rage.

'Ah, I was too foolish. The one outside, and the one inside, they are both... demons.'

His mouth trembled as he looked at Junpei's monstrous body that had crumpled to the ground. Junpei's eyes were filled with tears as he said, "Why?"

Mahito, seeing this, was about to speak when a fist had smashed into his face, caving in his nose. Mahito shocked, was gaping like a fish, before he smiled, "How did you hurt my soul? Could it be... you are aware of the shape of your soul?"

The only answer he got was a fist covered in cursed energy. They traded a few blows before Yuuji knocked Mahito through a window and jumping out after him.

While they were fighting, a crystalline ball had flown out of a nearby shadow before covering Junpei in a transparent goo. Then it grew smaller and condensed into a ball. Junpei's transformed figure had grown smaller with it and seemed to be floating within.

The Spade then shot out of the window and to a small warehouse a small distance away. There, Inei was sitting while hidden within the shadows. He reached his hand out and grabbed the Spade before examining the miniature Junpei.

Although he was originally planning to ambush Mahito then severely injure him before mind wiping and assimilating him, he had changed his mind. After all, he didn't want to hinder Yuuji's development. He needed Yuuji to realize that Sukuna was not his friend. He couldn't just befriend him like Naruto did to Kurama.

Plus, if everything went according to canon, Mahito would be left exhausted after the fight, his first domain expansion, and Sukuna's attack. Then, Inei could swoop in and easily take Mahito's ability. Of course, he would have to create a clone to send to Suguru Geto so that none of their plans would change dramatically.

While he was pondering about his future decisions, the battle was nearing its end. Kento Nanami had joined the battle and the two sorcerers weren't giving Mahito any chance to react to their beating. Right when they had thought that they had won, time seemed to slow.

Mahito's jaw seemed to drop down as two miniscule hands created a seal.

[Domain Expansion: Self Embodiment of Perfection]

Large hands seemed to appear out of nowhere before sectioning off Mahito and Nanami from Yuuji.

Yuuji started to pound on the exterior of the domain before he stopped. He took a deep breath in before climbing up to the roof of the school. Jumping off while also channeling his energy, he smashed into the top of the domain, causing Sukuna to attack Mahito.

The next few scenes went according to canon, with Mahito escaping through the sewers. After he had run for a while, he stopped and lay down on the ground, exhausted. Suddenly, a crystalline rope shot out from his shadow and restrained his hands and feet. A faint humanoid silhouette could be seen emerging from a nearby shadow.

"W-who are you?" Mahito's voice trembled as he said. Secretly, he was trying to stall out this conversation so he could regain some energy to escape. Unfortunately for him, Inei didn't care and placed his hand on Mahito's forehead.

A faint groaning sound came out of Mahito's mouth as his eyes rolled back into his head. Then, Inei activated his consensual assimilation and absorbed Mahito into his body.

Immediately, a current of strength flowed through Inei's body and it felt as if he had gained a new hand. He could instinctively use Idle transfiguration.

Before he did anything else, however, he summoned a Spade that had the body of a humanoid cursed spirit. Inei mindwiped it before implanting the memories Mahito had before he was assimilated. Then, he reshaped the body so that it looked like Mahito. This would be the new Mahito that he would send to Geto so that the plot stayed the same.

Taking out a new Spade, he poured in cursed energy that was infused with Mahito's cursed technique. Inei then used one of his claws to open an incision in Mahito's navel before stuffing the Spade inside. This would be the 'battery' that would power the new Mahito.

He would reprogram Mahito to ignore all signs that he wasn't the true one and to obey Inei's every command. He would also set a self destruct code so that as long as Yuuji shouted, "Die" at him, he would self-destruct.

With all that done, he teleported away through the shadows back to the highschool. Taking out Junpei and using his new power to good use, he put him back to normal. Lugging him over his shoulder, he jumped out the window and walked over to Yuuji, who was sitting down with his back against a wall, his eyes shut tightly.

"Itadori-kun~"

Yuuji, with his eyes full of tears, looked up to see a smiling Inei carrying an unconscious Junpei. His eyes widened in shock before he got up and pulled Inei into a tight hug.

----

Not much action from Inei, because I felt that this part was such an important development in JK that I just had to put it in.

Inei doesn't want to mess up the plot just yet as he wants to bait out all the enemies before progressing. He is still wary of the elders as there are many ways to break a pact without getting affected.