Kento Nanami vs. Mahito

Kento Nanami vs. Mahito is a battle fought between Grade 1 Jujutsu Sorcerer Kento Nanami and Special Grade Cursed Spirit, Mahito in the sewers of Kawasaki City.

Prologue
At their base of operations, Nanami, Yuji Itadori, and Kiyotaka Ijichi go over the data they've collected regarding the deaths and disappearance by disfiguration. Thanks to added intel from the Windows' on the killer's residuals, they're able to triangulate the position of the culprit's hideout.

Yuji is ready to move out and apprehend him, but Nanami says they still need to do more investigation since this is just an approximation. Instead, Nanami tasks Yuji with working together with Ijichi to investigate further into Junpei Yoshino, the only known witness at the theater.

Excited, Yuji leaves to gather information on Junpei. Ijichi asks why Nanami lied about the info being an approximation. Nanami replies that the killer is purposely leading pursuers to their lair. He's simply choosing not to out Yuji in danger. Yuji suddenly returns to the room to remind Nanami to be careful.

Shortly after Yuji and Ijichi leave to pursue Junpei, Nanami goes underground and is met with a number of disfigured ex-humans. He's able to effortlessly dispatch them, but Nanami expresses that killing humans isn't to his pleasure regardless. Nanami demands the killer show himself and on cue, Mahito appears from the shadows of the sewers and confronts the jujutsu sorcerer.

Mahito claims he's glad Satoru Gojo didn't show up and adds that someone too weak wouldn't be worth the effort. Nanami simply replies that he doesn't like working overtime, so they need to finish this as soon as possible.

Battle
With hands of surging cursed energy, Mahito attempts to strike his opponent. However, Nanami uses the back of the handle of his sword to knock away Mahito's left hand while using his elbow to stop Mahito's right hand at the same time. Nanami follows up with a straight kick that knocks Mahito back and then winds up his blunt wword, activating Ratio Technique.

Mahito attempts to guard himself but his arm breaks due to Nanami's cursed eechnique. He questions what happened and believes he defended with cursed energy. This sparks a conversation over the origin of the soul. Nanami decides to humor Mahito because he's surprised he can communicate like a normal human despite being a cursed spirit.

Mahito's cursed technique; Idle Transfiguration allows him to manipulate the soul, thus transforming the body. He does this to heal his broken arm and then uses it to transform a miniature ex-human into a curse-like creature. Irritated, Nanami checks his watch and claims he's clocking out after eight hours no matter what.

Nanami is able to instantly cleave the creature in half using his Ratio Technique. Mahito creates space and transforms miniaturized ex-humans into long poles of hard flesh. To counter, Mahito stabs his sword into the nearby wall and lifts his legs high enough to avoid Mahito's attack completely. He balances himself on top his new foothold and confirms for himself that his Ratio Technique is a bad matchup for Mahito's Idle Transfiguration.

The disfigured ex-human Nanami is standing on calls out for help. This reminds him that Shoko told him to kill these people out of mercy no matter what. Mahito apologizes for the distraction but Nanami angrily replies that he doesn't bring feelings into work. The cursed spirit laughs at the human and calls him a bad liar, claiming that his spirit is wavering.

Mahito asks the jujutsu sorcrerer what rank he is and Nanami reveals he's grade 1. Mahito says that's why his opponent is so strong and claims he's perfect for experimentation. Suddenly, Mahito blitzes completely past Nanami's guard and manages to touch the lower right side of his torso. He activates his cursed technique, injuring Nanami's side, who swipes at his opponent to get him away.

Mahito mocks Nanami and reveals he changed his legs shape to make him faster, granting him the speed needed to take Nanami off guard. Nanami falls on one knee in pain while Mahito explains that the jujutsu sorcerer would be dead if not for subconsciously protecting his soul with cursed energy. However, after two or three more hits, Nanami won't survive.

Nanami is able to avoid his opponent until 6:00 PM. Mahito mocks him for running but begins to notice that his opponent's cursed energy is rising fast. Nanami reveals that "Overtime" has begun and wraps his necktie around his right hand. Mahito surmises that Nanami has been restricting himself based on time. The jujutsu sorcerer begins divulging the properties of his cursed technique, prompting Mahito to realize that his opponent is going all out.

At this point Nanami only believes he has two options. Either he keeps fighting until Mahito runs out of cursed energy, which is not realistic, or he completely destroys him with a single blow. Nanami makes a mad dash for the nearby wall, all while Mahito pursues while claiming the grade 1 sorcerer is fleeing again, Nanami leaps toward the wall and focuses all his strength into a single blow. Nanami creates a weak point in the structure of the wall and strikes it with an incredibly powerful punch, unleashing the full might of Ratio Technique: Collapse!

The force of the impact completely implodes the walls with streaks of cursed energy. Mahito is taken back by the incredible raw power of the expanded cursed technique and decides his best option is to dodge. However, Nanami takes him off guard and uses Ratio Technique to take out Mahito's left leg. While on the ground, Mahito listens to Nanami say that they'll meet again, shortly before a large piece of debris crushes him.

Aftermath
Mahito manages to survive the encounter and shifts the shape of his body to escape the rubble. Suguru Geto arrives to check on Mahito's condition and comments that both fighters went all out. Mahito was able to learn a lot from fighting such an interesting opponent.

No matter what happens to his body, as long as Mahito's soul stays intact, he can survive even if he's crushed. Geto asks what became of Mahito's opponent but he's unsure and says he might still be trapped underneath all the rubble.

Nanami manages to reach a public bathroom where he's able to slightly dress his wounds. He calls Ijichi to come pick him up so he can return to Jujutsu High for proper treatment. After hanging up, Nanami recalls Nanami's words and surmises that he's actually a very immature cursed spirit. If the jujutsu sorcerers allow him to become too strong, they will pass the point of no return.