Back in Kokichi's hideout, two people walked in. 

Kokichi: "I was beginning to think you forgot about me."

Getou: "We wouldn't dare. The consequences of cursed restriction are something you know better than anyone."

Mahito: "Yeesh! As always... It stinks of mold. And why is there a hole in the floor?"

Kokichi: "He was here before you."

Mahito: "He?"

Getou: "Hm... Why was he here?"

Kokichi: "Only to see the consequences of heavenly restriction."

Getou: "Heh. Only to see the consequences of his actions, typical."

Mahito: "OH... You're talking about him! Surprised he didn't kill you... So, why don't we just kill him ourselves, he's our enemy after all" 

Getou: "Not yet, Mahito. We agreed to heal his body with your idle transfiguration... In exchange for cooperation and information. We've made this binding vow with him. The killing part comes after you fix him up."

Mahito: "It would've been great to have used him in Shibuya... Oh well..."

Kokichi: " 'Don't lay a finger on anyone from Kyoto Jujutsu High.' You're the ones who broke the binding vow first."

Mahito: "But that was Hanami... Don't pin that on us!"

Kokichi: "I'm not here to argue details with a curse. Hurry up and heal me, you... scum."

Mahito: "Don't blame me if you turn into a caterpillar."

Getou: "Mahito. A binding vow made with another person... Is a whole different beast than a binding vow imposed on oneself. One of the differences... Is that the 'penalty' is unknown. When breaking a binding vow with oneself... The worst that can happen is losing what was gained. We can't take that risk. If we break the binding vow now, who knows when and what sort of retribution might come our way."

Mahito: "Yeah, yeah. You better be thankful. You're even lower than scum."

He said as he approached Kokichi and placed his hand on his forehead. Using his technique, Idle transfiguration to fix Kokichi's body. 

Kokichi stood up as the bandages around his body fell. He examined his hands, arms, and torso. Feeling finally like a normal person, the pain he constantly felt was now gone.

Mahito: "Boooring. How about showing some enthusiasm?"

Kokichi: "That... Comes after we settle our business.

Mahito: "True. Well then... Let's begin!"

Mahito got into his fight stance and multiple Mechamarus appeared behind Kokichi.

Getou: "Should I help?"

Mahito: "Hell no, he's my toy."

Kokichi's puppets rapidly approached Mahito, but the curse made his fist larger and destroyed the mechas with one swift movement. But as his arm returned to its normal size, Mahito noticed that Kokichi was now gone.

Mahito: He ran away. Well, it's not like he needs to kill us. "Boring... Right now, I want to fight more than go hunting, th... Ough?!"

Suddenly, the ground below Mahito began to collapse, but he managed to jump away, out of the room they were into a bridge. As a large figure began to emerge from the water.

Mahito: "HA HA! OH HELL YES!"

Mahito: "You were making this thing in secret? I guess you're not a shut-in for nothing." You're inside, I bet. Makes sense, since you don't want me to touch you. The cockpit... the throne of the soul... is the head!

Mechamaru: 'All systems Normal. Perception feedback blocked'

Activity Limit: 17 years, 5 months, 6 days.

Kokichi: "Tsk." A screen is up... Getou, huh. It's not just to let me out. It's also blocking radio waves... "It's not as easy without Gojo Satoru." Yes, I need Gojo Satoru so I can win. It doesn't matter how, as long as I get in touch with Gojo Satoru... I can let him know about the Shibuya plan. And I can get him to protect me... Nakatomi should be near also, but I don't think I can trust him... Trying to concentrate on Getou to get rid of the screen... Is way too dangerous with Mahito Here. I have to exorcise him first.

Kokichi gave a glance at Getou, which seemed to not mind about the whole scene.

Getou: Go on, don't mind me.

Kokichi: I'm at disadvantage. But I can win... I've seen everything. And the cursed energy I earned from it. All these years I spent bound... I don't have to be frugal.

He thought to himself as he remembered a certain blue-haired sorcerer.

Kokichi: "CHARGED: ONE YEAR! BURN THEM TO ASHES, MECHAMARU!

A powerful beam was shot from Mechamaru's right hand, destroying some of the bridge whilst also burning some parts of Mahito's face.

Mahito: Is he planning on burning me until I run out of cursed energy? "For starters, I'll get you out of that cockpit."

Kokichi: I can't wound Mahito's soul with Mechamaru's attacks. He should have noticed that as well by now.

Mechamaru began punching the bridge in an attempt to hit Mahito, but it was pointless since the curse would evade them all, before jumping into the lake and shapeshifting into a fish.

Kokichi:

Mechamaru charged its palms with cursed energy and punched the lake, creating an explosion. But yet again, it caused no harm to Mahito, which used his abilities to enlarge his arm and grab one of Mechamaru's neck wires and propel himself up.

Kokichi: You don't care about my attacks at all. You'll never stop being on the offensive. Mahito. That's why I'll use... This thing!

Kokichi held a strange canister, but what was more strange was it held inside.

Mahito used his enlarged arm to close the gap between them and punch Mechamaru with his big fist.

Kokichi: What absurd power! He'll break the armor if I'm careless

He placed the canister in an injector.

Mechamaru: 'technique loaded'

Kokichi: I only have four chances...! I'll finish this quickly!

Mechamaru pointed his right arm at Mahito, which now had grown wings replacing his arms and was hovering some meters in front of the cockpit. Mechamaru's index finger opened up and revealed a rocket-like artifact.

Kokichi: "Fire! Mechamaru!"

The dart was shot and it hit Mahito in the left wing, burying itself in it some centimeters.

Mahito: "This is meaningless you know. Weren't you watching?"

But suddenly, it exploded, surprising Mahito, leaving him open for an attack, and Mechamaru swatted him like a fly, sending him to some trees. His left wing ripped off.

Mahito: What the hell? My soul was destroyed along with it...!

Mechamaru sent a barrage of punches to where Mahito was, but he shapeshifted into a bird/person and evaded the attack.

Kokichi: "Tsk. A bird again! Your moves are getting repetitive!" The left arm I just destroyed... It regenerated!... Wait, no... He kneaded the shape of his soul... To make it seem like it regenerated. The fact that he's showing it off is proof! It's fine! My trick...

Getou: "... It's working." He's good. It might be temporary but that's a special-grade level of cursed energy firepower. And he's prepared a countermeasure for Mahito as well. "Depending on the situation right here..."

Kokichi: "Charge: 5 Years!

Multiple spheres of cursed energy appeared then each one fired a beam of cursed energy straight at Mahito. He turned into his normal form and dodged them, but Mechamaru sent a punch that he barely dodged, but wasn't able to do it a second time and got sent flying into a tree.

Kokichi: I can do this...! 

Mechamaru: 'Technique loaded'

Kokichi: I can win! I will join... Everyone!

Mahito: "There. I win"

As Mahito's territory surrounded them, Mechamaru fell to the ground. 

Mahito: "Even if I can't touch you directly... That won't matter once you come into my domain. You get it, don't you? We're about 10 days from Halloween. Did you think I wouldn't use my territory because I have to save up my cursed energy? I can recover just fine in those 10 days. Don't bet all your hopes and dreams on a single plan, man. It's so pitiful that I don't even know what face I should be making."

Unknowing to him as he turned his back on Mechamaru, he pierced Mahito with his middle finger loaded with the technique.

Mahito: "Huh?"

Kokichi: That technique is sealed in this. It's the only way I can complete the technique by myself. I had four of these. The first one failed, I needed the second to protect my cockpit from his domain, and the third... When Jujutsu was at its 'peak', it was a technique used to protect one's disciple from astute evildoers, curse users, and cursed spirits. Ashiya Sadatsuna developed it in the Heian Era... To protect the inheritance of the technique within the clan, spreading this technique to those outside the clan was prohibited with a binding. It was a technique to protect oneself from a territory. A territory of the weak. I've seen... Everything.

 As Mahito exploded, the territory dissipated and Mechamaru let out a victory roar.

Getou: "Simple territory!" A territory that neutralizes all techniques. Inside a territory, an attack will hit anyone. Even Gojo Satoru. It's called 'simple' but... Even if it's simple, it can damage Mahito regardless of the technique used against him.

Kokichi: "Now you can't just stand there watching anymore... Getou!" What a serendipitous miscalculation. I still have one simple domain left... And nine years' worth of cursed energy that I can use against Getou! I can win! I will join... Everyone! "FIRE MECHAMARU!"

But just before he could do anything, the front side of the cockpit was destroyed, and a caterpillar-like version of Mahito appeared, crawling toward Kokichi.

Kokichi: I didn't finish him off?! But I still have one territory left! I'll just stab it! DIRECTLY!

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Back in Kyoto Jujutsu Tech, (y/n) was walking around the garden when Miwa appeared behind him.

Miwa: "(y/n)-san, do you know the whereabouts of Mechamaru... I haven't seen him recently."

(y/n): "Oh, Miwa-san... I don't know. Ever since I saw you some days ago with him I haven't seen Mechamaru."

Miwa: "I don't know but... I feel worried. I know he's probably okay but... I just have this feeling."

(y/n): "Don't worry Miwa-san. It's alright, I bet he's fine anyways... I could go search for him, and give him a good slap for worrying you."

Miwa: "N-no! Don't!"

(y/n): "Hehe. I'll go look out for him later, what do you think?"

Miwa: "thanks... But no slapping!"

(y/n): "Meany."

Miwa: "Hey! You said you would slap him!"

(y/n): "Not the same."

Miwa: "What?"

(y/n): "Anyways... I'll go now. I don't want to come back late."

Miwa: "Oh... Then...C-can I come with you?"

(y/n): "You could but... I... I have to do something important also... Yeah."

Miwa: "What is it?"

(y/n): "Just some... personal... stuff... Yeah."

Miwa: "Personal? Why are you saying Yeah all of a sudden..."

(y/n): "Not important. I'll go now!"

Miwa: "R-right. When you come back tell me how is he."

(y/n): "Right. See ya!"

(y/n) quickly turned around and began to sprint towards the entrance, making some ideas of Kokichi's current state.

Miwa: Mechamaru... I'm going to visit you someday.

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Time passed and (y/n) was now where he had found Mechamaru the last time, but now met with a different scene.

(y/n): "Should've guessed... Cool robot thing tho... That's a lot of blood, like a lot. 

I don't even want to look inside. Shit happens I guess... How am I going to tell this to Miwa? I'm feeling pity for you." 

Mai: "Eh? One of these again? What for now?"

Momo: "I don't know... The author's running out of ideas."

Miwa: "Does he think there's a demand for this or something?"

Mai: "I don't know."

(y/n): "We've run out of ideas three shorts ago."

Mai: "How so?"

(y/n): "Wack ideas."

Momo: "Why don't we just cancel these."

(y/n): "Helps to distract I guess."

Miwa: "What day is it again?"

Momo: "30th of October."

Miwa: "Halloween's tomorrow!"

Mai: "Hm. What will your costumes be?"

Momo/(y/n): "Costume?"

Miwa: "I... didn't buy one. They're expensive and..."

Mai: "really."