Modulo Chapter 4

A pupil stuck repeating first grade across three school years draws the attention of Yuka, Tsurugi, and Maru, who set out to learn why.

Neither sibling reacts much when Usami confirms that Maru is an alien. The plan to keep his nature secret collapsed, he says, once Maru blew his own cover, so the lid on Simurian intelligence has come off. Even so, the trio keeps working together, which thrills Maru. Out of earshot, Usami confides to Tsurugi that he believes the Simurians are really after jujutsu knowledge and asks him to keep a quiet eye on Maru; the boy agrees with reluctance. Mino then lays out the assignment: at Shuei Elementary a single student has stayed in first grade three years straight, surfacing each year under a tweaked name, Masayoshi, then Masaaki, now Masaki, while his face never ages. A teacher who phoned the parents got nothing but a broken recording. Every year this identical child slips away with his family right before moving up, only to reappear at the very same address with a fresh name. Reading it as a curse user posing as kids and slaughtering their households, Mino cautions that they might have to handle the culprit without him. Yuka and Mino head for the home; the boys go after the child.

Catching sight of Masaki after class, Tsurugi and Maru tail him, but a direct confrontation sends the panicked boy sprinting off. Mid-pursuit a cursed spirit rises behind the child, parrying their blows while making no attempt to hurt him, which leads Tsurugi to label it a protective shikigami even as Maru calls it a Kalyan. The boy crumples into apologies, and over at a park he recounts discovering his mother's body three years prior and pleading to remain a first grader forever, a wish her lingering soul fulfilled. Tsurugi figures the loss sent the child's jujutsu spiraling out of control. Going by his true name, Masayoshi, the boy guides the pair home, and inside they turn up bones he weeps over and admits belong to the mother he buried. Tsurugi promises he faces no arrest, only enrollment at Jujutsu High to master his power, while Maru, touched by the sorrow, says he wants to be the boy's neighbor, the kind of friend who grasps why his feelings count. Right then Yuka phones in, having found five corpses at the house of Masaki Takeda, supposedly the same address where they stand. The deception clicks for Tsurugi as he spins around to see Maru knocked cold, and the boy peels the skin off his face to reveal an old man underneath, grumbling that his ruse is over.