Assassin Exhibition of the Century Arc

This is the eighth story arc of the Sakamoto Days series, spanning chapters 131 through 168 across volumes 15 to 19. Back from Thailand, Sakamoto's group learns from Kashima that Uzuki intends to kill the current JAA chairman during the Assassin Exhibition of the Century. When the Order refuses to shut the event down, Sakamoto and his allies decide to slip inside and stop the scheme before it can unfold.

Word reaches Sakamoto through Kashima that Uzuki means to kill the sitting JAA chairman, Sei Asaki, during the grand Assassin Exhibition of the Century. When the Order flatly refuses to call the showcase off, Sakamoto's group resolves to slip inside and disarm the plot themselves. Hana whisks the salvaged cyborg Kashima away for a joyride and rebuilds his ruined frame with treads, a propeller fan, and grabber-claw arms, and after he instinctively shields her from a runaway car, he agrees to help on the condition that Uzuki be spared.

Kashima explains that Uzuki has splintered into separate selves, with a Rion-based persona driving his most extreme schemes, then names the target date and venue: the Okutabi museum, rigged to blow while Asaki tours the exhibit. Barred from buying sold-out tickets, the crew wins entry through a black-market auction, outbidding the Order sniper Kamihate, whom Heisuke later fights and befriends. Sakamoto, Shin, and Amane go in with Kaji standing in for the injured Heisuke.

Inside, Kaji discovers that Mafuyu himself is a walking bomb, one of a pair of decoys meant to detonate when the Order kills them. Shin, Osaragi, and an invisible Natsuki collide over Mafuyu before Natsuki surgically extracts the device, which Shin freezes and hurls clear of the building to explode in open air. As the museum seals shut into chaos, Gaku, Haruma, Kumanomi, and Carolina Reaper crash in from a helicopter, and Gaku collides with Nagumo in a brutal, drawn-out duel.

The infiltration exposes the layered truth of Uzuki's mind. Sei Asaki turns out to be Uzuki's own elder brother, the persona called Akao proves to be Uzuki's invention, and it emerges that Akao placed the original bounty on Sakamoto precisely so that he would one day kill Uzuki. Nagumo's attempt on Uzuki fails against his unusual physiology, and for his defiance Nagumo is cast out of the Order, after which he, Sakamoto, and Uzuki are all branded top-priority targets.

The bloodshed peaks when Takamura storms in and turns on Uzuki's people, slaying Haruma as he guards his leader and running Gaku through the chest, leaving his fate unconfirmed. Traumatized by watching his allies fall, Uzuki spins up a fresh personality modeled on Takamura and then kills the old man himself. Shishiba, gravely wounded shielding Amane, confesses to the boy that he was the one who killed his father, while the reshaped Order, now led by the newly revealed Oki, sets its sights on capturing Sakamoto, Nagumo, and Uzuki, carrying the conflict into the JAA Jail Arc.