Mahito/Synopsis

History
Mahito was born from the hate and fear humans have for each other.

At some point Mahito enacted a binding vow with Kokichi Muta, in which Mahito would heal Kokichi. In return, Kokichi would act as mole within Jujutsu High and supply them with information.

Fearsome Womb Arc
Mahito is first seen sitting under an umbrella on a beach chair within Dagon's Domain Expansion and reading a book when Pseudo-Geto first arrives. Mahito agrees with Geto, about sealing Satoru Gojo on a set date that he will contact them with.

Vs. Mahito Arc
At a later day, Mahito meets Junpei Yoshino after having killed three people at a theater. He then heads into the sewer with Junpei, where Mahito explains to Junpei what cursed spirits are. Junpei asks what kind of spirit Mahito is, to which Mahito replies that he is a cursed spirit that was created from people fearing other people. Mahito and Junpei then talk with about human emotion while Mahito shows Junpei his human experiments.

Later Mahito encounters Kento Nanami, and the two start to fight. After a little bit, Mahito starts to explain his abilities. The two continue to fight, Mahito notices that Nanami's power is increasing after it hits 6 o'clock. As Mahito prepares to continue fighting, Nanami escapes by burying Mahito in rubble. Mahito manages to escape from the rubble after sometime and meets with Geto.

After Junpei's mother is killed, Mahito shows Junpei the cursed object that caused it and suggest that it was the classmate that was bullying Junpei that did it. Mahito then help Junpei prepare to attack his classmates.

Mahito shows up during the fight between Yuji Itadori and Junpei. Mahito restrains Yuji, and uses his abilities to transforms Junpei. Mahito then laughs when Sukuna refuses to help Yuji. Mahito continues to laugh even after Junpei dies, at which point Yuji punches him. Mahito notices that there was something different about that punch and realizes that Yuji can naturally injure him. Mahito then takes on Yuji, and manages to force Yuji to the courtyard. Mahito manages to pin Yuji down and tries to force Yuji to switch with Sukuna, but Sukuna forces Mahito out of his territory and tells him there won't be another chance.

Mahito and Yuji continue to fight, until Nanami shows up and attacks Mahito. Mahito then takes on both Yuji and Nanami, and manages to dodge most of their attacks. Mahito manages to distracts Yuji and restrain Nanami. As Mahito prepares to finish Nanami off, Yuji shows up and hit Mahito. Mahito is then repeatedly hit by both Yuji and Nanami, until he uses his Domain Expansion to trap Nanami. Mahito prepares to attack Nanami but when Yuji forcibly enters his territory, Mahito is wounded by Sukuna. Mahito uses the last of his power to distract Yuji and escape from the area. Mahito then recovers in the sewer, and thinks about how powerful Sukuna is and how he will kill Yuji next.

Kyoto Goodwill Event Arc
Later Mahito and Geto meet up with Jogo. Mahito talks with Geto and Jogo about how he is for Geto's plans and how they will retrieve the fingers that are at the Tokyo College. Mahito later attends another meeting with the others about how they will invade the Tokyo College.

During the Kyoto Goodwill Event, Mahito shows up at the site along with Hanami, Juzo Kumiya, and Haruta Shigemo. Mahito heads over to where Sukuna's fingers are at, while the others distract the sorcerers. Mahito manages to obtain the fingers, along with three of the Death Painting Wombs. Mahito then meets up with Hanami and Haruta, where he helps a wounded Hanami leave the site.

Death Painting Arc
Days later, Mahito feeds the Death Painting Wombs to humans, in order to give them bodies. Later Mahito is playing a board game along with Geto and Choso, when Choso reveals that his brothers are dead. Mahito is more concerned by the fact that Choso had destroyed a piece, but smile when he learns that Yuji and his classmate are the ones who are responsible.

Shibuya Incident Arc
Days later, Mahito and Geto goes to meet with Kokichi Muta. Once they reach Kokichi's location, Mahito comments about the smell and how he just wants to kill Kokichi, to which Geto replies that they can kill him after Mahito heals Kokichi's body. Kokichi tells them to hurry up and heal him, and Mahito tells remarks to not complain if he turns him into a caterpillar instead. Geto tells Mahito that it would be dangerous for Mahito to break their vow, at which point Mahito agrees to heal Kokichi. Mahito then uses Idle Transfiguration on Kokichi to heal his body. After Kokichi's body is healed, Mahito and Kokichi begin to fight. Geto offers to help out, but Mahito decline since Kokichi is his toy. As Kokichi sends multiple Mechamaru's out, Mahito takes them all out but notices that Kokichi has fled. As Mahito complains how he doesn't want to hunt Kokichi down, the floor suddenly collapses below him.

Mahito quickly exits the building and is confronted by Kokichi's Ultimate Mechamaru puppet. Mahito figures that Kokichi is inside of the puppet since Kokichi doesn't want him to touch him. Mahito quickly dodges multiple of Kokichi's attacks, and manages to grab a hold of the Ultimate Mechamaru. Mahito manages to land a blow on Mechmaru, at which point Kokichi notices that Mahito will be able to break the armor if he is careless. Mahito then starts to transform, which Kokichi uses as a chance to fire a bomb that lands on Mahito. Mahito says that that was meaningless, but suddenly it goes off and takes off Mahito's arm. As Mahito is shocked by this, Kokichi takes this chance to slam Mahito into the ground. After Mahito lands on the ground, he notices that his soul was destroyed along with his arm. Kokichi starts to rapidly pound the ground, but Mahito manages to slip away. As he flies away, Mahito manages to reshape his soul to create a makeshift arm. As Kokichi launches his Pigeon Viola technique, Mahito manages to slip past the technique. While dodging the attack, Mahito thinks about how he has to figure out which of Kokichi's attacks have an effect on his soul. When Kokichi attack again, Mahito dodges it but Kokichi manages to land a blow. As Kokichi prepares to launch another technique, Mahito manages to trap Kokichi within his territorial expansion.

Mahito then announces that he has won, and uses his Idle Mutation on Kokichi. As Mechamaru falls to the ground, Mahito gloats about how he was won and turns around to leave. Suddenly Mahito is pierced by Mechamaru, and his body explodes when Kokichi uses a technique on it. As Mahito's territorial expansion is dispelled, Kokichi turns his attention to Geto and prepares to fight. Suddenly Mahito breaks into Mechamaru's cockpit and attacks Kokichi. After the fight is finished, Mahito and Geto leave. As they leave, Mahito and Geto talk about the fight and how they were able to test the screen for their objective.

Sometime later, Mahito is playing mahjong with Hanami, Jogo, and Geto, during which Geto explains how the Prison Realm works.

On October 31, Mahito created multiple transfigured humans and put them in the curtain at Meiji-jingumae Station. Mahito is at the Tokyo Station when he senses that the curtain he has created, has been raised. Mahito figures that a strong sorcerer had done it and wants to fight them, but has work to do. Mahito then mutates all the humans and takes them to Shibuya by train. Once they arrive at Shibuya, Mahito greets Jogo while the mutated humans attack the other humans present. Mahito comments about how the air smell great since it is full of fear. Mahito comments about how they should keep some humans alive and hunt them in a forest, to which Jogo says that he will just burn the forest down. Mahito says that Hanami will get mad, but Jogo says that Hanami is dead much to Mahito's surprise.

As the mutated humans start to attack the humans, Mahito goes to attack Gojo but notices that he can't hit him. As Gojo attacks Mahito, more humans are fall down into the subway from above, Mahito and Choso use a technique to attack Gojo but all it does is kill the humans that are around Gojo. As all their attacks fail, Mahito thinks about how Gojo is different from Yuji. Mahito is shocked when Gojo activates his Domain Expansion. Mahito is then stunned after Gojo activates his Domain Expansion for less then a second. Leaving all the curses and transfigured humans stunned for several minutes.

After Mahito recovers he sees that Gojo is being sealed by Geto. When Geto's arm takes control again, he tells Mahito that memories must exist inside the body as well as the soul. Mahito replies that this might be a unique case and would not apply to his own cursed technique, which Geto enjoys as their techniques dictate this world. Mahito then watches as Gojo is sealed inside of the Prison Realm. Mahito asks if they can use the object again, to which Geto replies that the Prison Realm can only have one occupant. When Choso and Jogo get over being stunned, Mahito watches as the Prison Realm forces its way to the ground. Geto explains how the Prison Realm is processing Gojo and is can't be moved, only for them to realize Kokichi was spying on them. After Yuji shouts about what has happened to Gojo, the group debate about what to do. When Jogo is angered by Choso's desire to kill Yuji, Mahito explains to everyone that they don't need Sukuna anymore since they have sealed Gojo. As Jogo continues to say that they still need Sukuna awakened for their plans, Mahito says that he doesn't want to fight Jogo and then propose were the first to find Yuji can decide what to do with him. As Choso agrees to this, Mahito asks what the impostor Geto plans to do. The impostor says that he will stay and watch the Prison Realm. Mahito silently reacts to imposter Geto's words, implying that he may be skeptical of the response he was given. As Jogo says that they should stay at the station more sorcerers are heading to their location, but Mahito and the other spirits leave the station to find Yuji while Jogo is talking. Once the others leave, Mahito splits himself into two and both leave after Dagon eat the humans in their way. Jogo tries to chase after him but Mahito blocks his way. He would also split himself into two parts.

Later the real Mahito would watch as a wounded Nanami walks by while hiding in a photo booth. After Nanami deals with some mutated humans, Mahito places his hand on Nanami's chest and the two have a small chat. When Yuji suddenly arrives, Mahito kills Nanami and turns his attention to Yuji. As Yuji charges, Mahito distracts Yuji's attention and gets behind him. Mahito attacks with his Body Repel attack, which Yuji manages to stop. Suddenly Mahito appears from the attack and lands a blow on Yuji. Yuji asks why Mahito can kill so easily, to which Mahito replies that Yuji is Mahito. Mahito also says that Yuji wouldn't be able to defeat him until he accepts that. Yuji says that he will make those Mahito's last words, and takes a stance. Mahito thinks about how he has to manipulate himself to be tougher since his other tactics won't work. Mahito takes a stance and starts to inch forward, while planning to pierce Yuji's heart. Mahito manages to get close enough and attacks, but Yuji dodges and lands a kick on Mahito. Mahito recollects himself and compliments Yuji, but also says that they will now begin round two. Mahito then takes a more tactical approach and starts attacking from a distance while running away. Mahito manages to escape Yuji's sight and hide within a human, and manages to land a blow on Yuji when he lets his guard down. Mahito then uses another human to create a sword, and thinks about how he is going to break Yuji's mind.

Elsewhere, the second Mahito comes across Nobara and the two have a brief chat. When Nobara attacks with her cursed nails, Mahito manages to dodge them. Nobara then blocks Mahito's view with a sign and lands a blow with her Hairpin technique, to which Mahito tells her that that her technique won't work. Mahito figures that Nobara is a friend of Yuji's and that bringing her dead body would break Yuji. While the clone is unable to use the original's cursed technique, it is initially unimpressed by Nobara's ability. Initially it seems that Mahito has the upper hand, only to be shocked when Nobara's Resonance ability attacks his soul directly. The damage of Nobara's attacks towards the clone resonate with the original and bounce back to the clone, leaving them both stunned. Mahito's vulnerability allows Yuji to launch a rush of punishing blows. To deal with this crisis, both Mahitos flee from the battle and force their enemies to follow. The two Mahitos run past each other in the Subway hallway, trapped between Nobara and Yuji. The double rushes towards Yuji while the original touches a confused Nobara. Yuji kills the duplicate only to see Mahito transfigure Nobara's face, blasting it open and destroying one of her eyes

As Yuji's resolve completely shatters looking at his friend's body, Mahito runs towards him and strikes him with Black Flash. With his mortal enemy unable to fight back, Mahito gleefully beats Yuji while screaming about his naivety and claiming this battle is a fight between two incompatible species and truths. When he goes for the killing blow, Mahito is teleported to the other side of the hallway by the newly arrived Todo.

Even knowing about Todo's ability, Mahito struggles against it. As their fight continues Mahito realizes that he needs to experience Black Flash again in order to truly understand the nature of his own soul. In his haste he attacks Todo only for him to switch places with a revived and focused Yuji. Yuji hits Mahito with his own Black Flash and knocks him away, preparing to fight him alongside Todo. Deciding that Todo is the main problem, Mahito plans on killing him first. Todo manages to trigger his own Black Flash but Mahito blocks it and is completely unharmed because his soul wasn't affected. Using Soul Multiplicity: Body Repel, Mahito forces the battle onto the city streets and says this will be their last chance.

Using his Polymorphic Soul Isomer, Mahito is able to force Todo through a building and away from Yuji so that he can focus his attacks on Yuji, only for the Grade 1 student to quickly return. Taking inspiration from Gojo and the awakening of Black Flash, Mahito uses his Domain Expansion for less then a second. This last resort attack causes him to appear before Sukuna where Mahito tells the King of Curses to stand aside as he kills Yuji. The attack forces Todo to sever his left hand before the transfiguration spreads, only for Mahito to trigger another Black Flash attack, as his abilities were temporarily depleted following his expansion. Todo shocks Mahito by slapping Mahito's hand with his remaining right as a substitute for clapping, triggering Boogie Woogie and letting him swap again with a battle ready Yuji. Enduring another Black Flash, Mahito uses Polymorphic Soul to buy time. Using Black Flash twice finally gives Mahito an understanding of his true soul and his true form. Ripping his face off, Mahito begins his transformation: Instant Spirit Body of Distorted Killing.

With his new form, Mahito decides that killing Yuji will mark the start of his true life. His overwhelming power and impenetrable skin place Mahito on an entirely new level. As he is hammered through the ground, Yuji decides that his only chance is to use all his remaining strength in one attack enhanced by a third Black Flash. Mahito pauses, briefly coughing up blood, the damage of Yuji's previous Black Flash punch still lingering. The pair once again get in range, gambling everything on one final attack. Mahito creates an opening in his defenses to bait Yuji's attack, only to be taken by surprise when Yuji uses Divergent Fist and knocks him off balance. As Yuji dodges the killing blow, Mahito hears Todo clapping and turns around, only to see that they have not swapped places and Yuji is still in front of him. Yuji deals a crushing blow to Mahito's side, knocking him out of his Distorted Killing form. A terrified and desperate Mahito tries vomit up more of his transfigured humans only to find that he has run out. Yuji looks down on him and promises to kill him: no matter how much time passes or how many times they are reborn, Yuji promises to kill Mahito again and again with no need to justify his actions as anything but his nature. Mahito turns to run from his mortal enemy, only to stumble and fall. Pseudo-Geto arrives and asks Mahito if he wants to be saved, and then effortlessly beats Yuji with a barrage of curses. Mahito however lashes out at his ally, telling him he always knew what his plan for him was. Moments later, Pseudo-Geto uses his vessel's Cursed Spirit Manipulation technique to seal and absorb Mahito. After speaking with Yuji about Geto's power, he then eats the sphere which Mahito is sealed in. When he is attacked by the Kyoto Jujutsu High Crew, he uses Mahito and other 1st and upper grades to activate an Uzumaki and defeat the opponents. After a conversation with Yuji, Pseudo-Geto uses Mahito's cursed technique to become some marked people in two groups of select sorcerers: the first group gains the ability to gain a cursed technique, while the second is adapted as vessel of past sorcerers like Sukuna.