Kokichi Muta

Kokichi Muta is a character in Jujutsu Kaisen. He is a second-year at Kyoto Magic Technical College, but due to his Heavenly Bound, he uses a puppet and the alias Mechamaru Ultimate (メカ) to attend school and do missions.

Goodwill Event Arc
Mechamaru arrives at the Tokyo College for the Goodwill Event, along with the other Kyoto College students and teachers. When the Kyoto students notice that Tokyo students, he takes with the others about how Okkotsu is not their. Mechamaru is there when Gojo arrives and reveals that Sukuna's host, Yuji, is alive.

Later Mechamaru attends the pre-event meeting with the other Kyoto students and principal Yoshinobu. As Yoshinoby instructs them to kill Yuji, Aoi gets annoyed by this and leaves after threatening them all. Mechamaru then talks with the other about what to do with Yuji and Aoi. Mechamaru also has concerns about Toge, which Noritoshi says that Toge will not be a problem.

When the events begins, Mechamaru along with the other Kyoto student head towards where Yuji is at. When Yuji is separated from the rest of his group, Mechamaru and other Kyoto students surround and attack Yuji. As the Kyoto students prepare to finish Yuji off, Aoi arrives and saves Yuji. After Aoi confront the other students, Mechamaru and the others decide to leave Yuji to Aoi.

After retreating, Mechamaru manages to come across Panda and Nobara. Mechamaru manages to wound Panda and gets close after thinks that Panda is dead. When Panda reveals that he was just playing dead, Mechamaru is hit by Panda. When Panda comments about how they are the same, Mechamaru gets angry and prepares to attack Panda. Mechamaru attacks with a technique, but Panda manages to dodge it. As Panda wonders about how strong Mechamaru is, Mechamaru reveals that he is stronger then Panda. Mechamaru then fires a blast at Panda, but Panda manages to with stand it. Mechamaru and Panda then continue to fight, with Mechamaru being on the losing side. Mechamaru and Panda start to talk, were Mechamaru reveal what kind of condition his real body is in. Mechamaru then enters Mode: Albatross and fires a larger blast, which Panda decides to take since the blast would hit his comrade if he didn't.

Mechamaru thinks he has won and starts to walk away, when Panda is revealed to be alive and has changed shape. As Panda attacks Mechamaru, Mechamaru tries to defend but Panda easily manages to damage him. As Mechamaru is flung to a different location, Mechamaru thinks about how Panda's techniques work. Mechamaru thinks about how much damage he has taken and what he is capable of doing. Mechamaru and Panda continue their fight, where Mechamaru fires an attack at Panda's core. Panda reveals that that was a false core and lands a blow on Mechamaru. As Mechamaru can no longer fight, Mechamaru and Panda begin to talk. After the conversation, Panda asks to borrow his phone which Mechamaru lends it to him.

On the second day of the event, Mechamaru participates in a baseball game as a pitching machine much to the other teams anger. After the Goodwill Event comes to an end, Mechamaru heads back to Kyoto along with the others.

Current Arc
Sometime later, Kasumi Miwa informs Kokichi that their notebooks are due that day which Kokichi informs her where his notebook is and that he will be asleep for a bit. Kokichi then meets with Getou and Mahito, and complains to them about how they weren't suppose to attack the Kyoto students during the exchange but they simply pass the blame on Hanami. Mahito comments about killing Kokichi, but Getou tells him that they have to heal him first or sometime will happen to them. Mahito then uses his Idle Transfiguration on Kokichi, which restores his body to perfect condition. Once Kokichi is healed, Kokichi and Mahito prepare to fight each other. Kokichi manages to distract Mahito by sending multiple puppets out.

Kokichi uses this chance to get into his Ultimate Mechamaru puppet and uses it to force Mahito out of the building. Kokichi notices that Getou has put up a screen that has blocked him from escaping or contacting people. Kokichi thinks about how he has to contact Getou for help and to inform him about the Shibuya Plan. Kokichi also thinks about how he has to take care of Mahito first before he can deal with the screen. Kokichi thinks about how he can't be frugal with all the cursed power that he has saved up and starts to fire blasts at Mahito. Mahito manages to dodge all Kokichi's attacks and grab a hold of Ultimate Mechimaru, which Kokichi thinks about how Mahito will always be on the offensive and that he prepared for this situation. As Mahito attacks the Mechamaru directly, Kokichi thinks about how Mahito would be able to break the armor if he is not careless. While Mahito starts to transform again, Kokichi manages to launch a bomb that destroys Mahito's left arm. As Mahito is stunned, Kokichi uses this chance to sent Mahito flying into the ground. As Mahito figures out that the bomb is able to destroy his soul along with his arm, Kokichi takes this chance to rapidly attack Mahito. As Mahito manages to slip away, Kokichi notices that Mahito arm has returned but figures that Mahito has just made it look like his arm had regenerated. Kokichi then fires his Pigeon Viola technique, but Mahito manages to evade the techniques. Kokichi manages to hit Mahito into the ground again, and prepares to launch another technique.

As Kokichi thinks that he will be able to win and join his friends, but is shocked when Mahito uses his territorial expansion. As Mahito uses his idle mutation on Kokichi, Mechmaru falls to the ground. Mahito gloats and turns away, which Kokichi uses this chance to pierce Mahito's body. Kokichi thinks about how the technique he is using is Miwa's Simple Territory and how the technique was developed along with how it works. As Kokichi uses the technique on Mahito, Mahito's body explodes and his Territorial Expansion disperses. Kokichi then turns his attention to Getou and prepares to attack but Mahito suddenly breaks into the cockpit. Kokichi then tries to stab Mahito with his last Simple Territory technique, while Mahito lunges at him. After the fight is over, Mechamaru is slumped over the dam, while it is unknown was had happened to Kokichi.

Abilities
Mechamaru Ultimate is a quasi-1st grade Shaman.

Cursed Power and Forms
Kokichi Muta's power is called Puppet Manipulation. This power allows him to manipulate puppets from a remote location. Because of Kokichi's heavenly restriction, Kokichi is capable of manipulating puppets all over the nation.
 * Mechamaru: Kokichi uses this mechanical puppet for his everyday use.
 * Sword Option: Multiple blades protrude from Mechamaru's forearm, along with his nail extending. Mechmaru is also capable of increasing the size of his forearm and having spikes protrude of it.
 * Ultra Spin: Mechamaru spins his hand and forearm, and swings his right arm at a target. This technique is capable of easy piercing through a tree trunk.
 * Ultra Shield: Mechmaru put up his guard, with his forearm in front of him, to block incoming attacks.
 * Boost On: Mechmaru releases cursed power from it's elbow to increase the speed of his attack.
 * Ultra Cannon: Mechmaru fires a blast of cursed power from that palm of his hand.
 * While in Mode: Albatross, Mechamaru's Ultra Cannon's power is increased. Mechamaru fires the technique from his mouth and both hands.
 * Mode: Albatross: Mechamaru protrudes a cannon from his mouth.
 * Ultimate Mechamaru: A large mechanical puppet that Kokichi is capable of piloting from the cockpit in the puppets head.
 * Ultra Cannon: Kokichi fires a blast of cursed power from the palm of the puppet's hand. This technique consumes one years worth of cursed power that Kokichi has saved up.
 * Miracle Cannon: Kokichi fires a blast of cursed power from both of his puppet's hands. This technique consumes two years worth of cursed power that Kokichi has saved up.
 * Vision Viola: Kokichi creates orbs made of cursed energy and fires blasts from them when released. The blasts follow the target until they come in contact with something. This technique consumes 5 years worth of cursed power that Kokichi has saved up.

Trivia

 * Mechamaru ranked 30th place in the manga's 1st Character Popularity Poll with 468 votes.