Kokichi Muta in Jujutsu Kaisen: Mechamaru and the Mole Explained

Kokichi Muta (与幸吉) is a second-year student at Kyoto Jujutsu High, a semi-grade 1 jujutsu sorcerer, and the person operating Ultimate Mechamaru — the wooden puppet that attends classes, goes on missions, and represents him to the outside world. His real body has never walked on grass. His skin burns in moonlight. He lives in a cave attached to tubes. He made a deal with Mahito to get a functioning body and immediately tried to kill him the moment the deal was honoured.

He is known to everyone as Mechamaru. Almost nobody knows his real name or face.

Character Profile

Who Is Kokichi Muta?

Kokichi Muta is a jujutsu sorcerer born with a Heavenly Restriction so severe that the act of living was physically agonising, who spent seventeen years building a puppet empire to participate in the world he could not physically enter, and who betrayed every sorcerer he knew because he wanted to feel sunlight on his skin.

He was taken into jujutsu society’s custody as an infant. His parents were told he had died. He grew up in a cave, immobile, his body wrapped in bandages, connected to tubes, missing his right arm from birth and his legs too weak to support weight below the knees. His skin was sensitive enough that moonlight caused burns. Every part of existing was pain.

In exchange for this body, his Heavenly Restriction gave him cursed energy output covering all of Japan and Puppet Manipulation technique capable of controlling multiple cursed corpses simultaneously across that range. He built Mechamaru — named after a robot from an anime he loved as a child — and used it to attend school, fight missions, and have conversations he could never have in person.

His classmate Kasumi Miwa told Mechamaru she would visit him someday. He never told her what visit actually meant.

What Is Puppet Manipulation?

Puppet Manipulation allows Kokichi to remotely control cursed corpse puppets across a range spanning all of Japan — a reach made possible by the massive cursed energy output his Heavenly Restriction granted him in exchange for his body.

His primary puppet is Ultimate Mechamaru — a humanoid wooden cursed corpse with emerald eyes, a spiral symbol on its chest, and a black jujutsu uniform. In standard form Mechamaru fights using extendable arms, a cannon that fires from its elbow joint called Ultra Cannon, and a high-output beam called Ultra Shield. It can project a Simple Domain to counter enemy Domain Expansions, protecting allies from guaranteed hits inside hostile domains.

Kokichi controls multiple smaller unregistered puppets simultaneously alongside Mechamaru — micro-sized units used for reconnaissance and information gathering. These smaller units are what he used to spy for Mahito and Kenjaku.

Ultimate Mechamaru Mode: Absolute

Mode: Absolute is Kokichi’s final form — a giant armoured version of Mechamaru fuelled by seventeen years of stored excess cursed energy. The accumulated reserves allow it to output Special Grade-level cursed energy momentarily, making it the most powerful thing Kokichi can produce. He built it as his killshot against Mahito. He deploys it the moment Mahito heals his body and immediately betrays him.

What Happens to Kokichi in the Story?

Kokichi operates as the Kyoto team’s Mechamaru through the Goodwill Event, makes a secret deal with Mahito to trade information for a healed body, gets his body healed, feels sunlight for the first time, immediately deploys Mode: Absolute against Mahito, and dies when seventeen years of stored energy is not enough.

Kyoto Goodwill Event and the Deal

Kokichi’s binding vow with Mahito requires him to relay insider information about Jujutsu High using his unregistered micro-puppets. In exchange Mahito agrees to heal his body using Idle Transfiguration. The deal includes one condition Kokichi insisted on: Mahito and his allies cannot harm anyone from Kyoto Jujutsu High.

When Hanami attacks the Kyoto Goodwill Event and harms Kyoto students, Kokichi withdraws from his mole role. The violation was committed by an ally of Mahito’s without Mahito’s direct involvement, but the spirit of the clause was broken. Kokichi stops providing information.

The Betrayal and Death

Mahito heals Kokichi using Idle Transfiguration — reshaping his soul and correcting every physical deformity. Kokichi’s right arm exists. His skin is whole. He walks outside for the first time. He feels sunlight.

Then he activates Mode: Absolute and tries to kill Mahito immediately.

The fight is genuinely impressive. Mode: Absolute pushes Mahito harder than most opponents do. Seventeen years of stored cursed energy deployed in a single extended battle is enough to momentarily hit Special Grade output. Mahito has to take it seriously.

It is not enough. Mahito’s Idle Transfiguration adapts faster than Kokichi’s systems can track. He dies in his healed body inside the cockpit of Mode: Absolute.

Before dying, Kokichi transmits everything he knows about the Shibuya operation to Mei Mei — using his puppet network one final time. The information reaches the jujutsu sorcerers preparing for Shibuya and contributes to their ability to respond at all. His betrayal costs him everything. His final act partially compensates for it.

He also sends a final message to Kasumi Miwa, telling her where his notebook is and saying he will be sleeping. She does not understand what it means until later.

Read this sequence from Chapter 83 through Chapter 90.

Why Does Kokichi Matter?

Kokichi is the manga’s most specific portrait of what the jujutsu world costs people it never chose to involve. He did not volunteer for this life. He was taken as an infant by an institution that told his parents he was dead, raised in a cave, and spent seventeen years building the tools he needed to participate in a world that had no accessible version of itself for him.

His deal with Mahito was wrong. It was also the most human decision in the series — a person in genuine pain choosing the available path toward normalcy over the institutionally approved path toward continued suffering. The manga does not excuse it. It understands it.

He died in a body that finally worked. He never met Kasumi Miwa in person.