Chapter 145

The Back is the one hundred and forty fifth chapter of Gege Akutami's Jujutsu Kaisen.

Summary
Tengen reveals that the being that took possession of Noritoshi Kamo and Suguru Geto is Kenjaku. He plans to force evolution upon every person in Japan by having Tengen "merge" with mankind. If that happens, the boundary between man and curses vanishes and evil will spread around the globe. With Tengen's evolution, they're at risk of cursed spirit manipulation. The purpose of the Culling Game is to initiate the merging process. With the rules, their only option is to participate. Along with that, they must find a way to release Gojo. They will need the help of Hana Kurusu and her ability to erase curse techniques.

Plot Details
Within the Tombs of the Star Corridor, Tsukumo asks why Tengen isn't greeting her, with them reply that this is not their first encounter. Tengen also has sealed off the tomb in case of them was allied with Kenjaku, an ancient sorcerer who inhabited the old Noritoshi Kamo and now Suguru Geto. Yuji suddenly interrupts and asks about Master Tengen's appearance, who says that they, despite being immortal, are not immune to aging. Tengen tells him that in 500 years, he'll look like this as well, surprising Yuji. Eleven years ago, with the death of Riko Amanai, the merger never happened and Tengen is starting to evolve. Tengen has become "one" with the world.

Fushiguro and Okkotsu asks about the Prison Realm. Tengen agrees under the condition that two will serve as his bodyguards from Choso, Okkotsu, and Tsukumo. Yuta wonders why they need guards even though they're immortal while Maki asks if they're worried about the seal. Yuki objects to this says it isn't fair because they haven't told them why and for how long they need to do it. Tengen states that Kenjaku's objective is to trigger evolution upon the citizens of Japan. Kenjaku couldn't do this during the Shibuya incident because cursed energy refined through Uzumaki is unable to go back to the sorcerer and triggering evolution to every person with a cursed technique is incredibly inefficient. Now, Kenjaku plans to trigger evolution by having Tengen "merge" with mankind.

The group question if it possible for Tengen to fuse with multiple people that aren't even Star Plasma Vessels. Tengen states that it's possible given their current evolutionary state. A human that fuses with Tengen becomes "something greater" than a sorcerer who both there and not there. Tengen maintains his form through his barrier techniques, but even a single person evolving or going berserk with end the world. That's because the line between curses and human will be erased, letting evil to spread sporadically. These impurity would quickly envelop the world like it has in Japan.

Yuji asks about Kenjaku, only for Tengen to reply that they don't know because Tengen can't read a human's "heart." Maki asks if Tengen could simply refuse the merger, but Tengen can't because Tengen's evolution has made them more cursed spirit than human and a target for Cursed Spirit Manipulation, shocking everyone. Given Kenjaku's abilities, he might be able to capture them if they encounter each other. Tengen's body is also rejecting everything at the Tomb of the Star Corridor. Kenjaku's power is only second to Tengen's and it's unclear when he plans to undo the seals on the tomb.

Tsukumo wonders why Kenjaku chose now to strike. Tengens explains that them, the Star Plasma Vessels, and the Six Eyes are connected by fate. Kenjaku was defeated twice in the past by a Six Eyes user. The second time, he didn't wait to kill both a Six Eyes user and a Star Plasma Vessel less than month following their birth. After that, there was merger with a Star Plasma Vessel and a Six Eyes user. With that, Kenjaku changed his plan to sealing the Six Eyes in prison since two bearers can't appear at the same time. Then, 11 years ago, Toji Zenin had appeared and destroyed their destinies. Finally, Suguru Geto's existence and his Cursed Spirit Manipulation. All of these pieces suddenly came together except the Prison Realm, winch was obtained six years later.

Megumi asks about the purpose of the Culling Game. Tengen explains that it's the way to break the body before the merge. It's isn't impossible for non-Plasma Vessel to merge with Tengen but it's highly unlikely and incomplete. The Culling Game's purpose is to use the player's curse energy and boundary-binding barriers to bring mankind to the other side. This would cause the merger with Tengen, but Kenjaku would have to undertake certain Binding Vows. One of the vows prevents him from being the game master, which would let the game persist past his death. The game will continue until all players perish or refuse participation and die and the rules ensure that nothing can interrupt the ritual.

In that case, Okkotsu states that they have no choice but to participate so they add a rule to allow unwilling participants such as Tsumiki to leave. Megumi states we also need to find a way to release Gojo from the Prison Realm. Choso and Tsukumo elect themselves as Tengen's bodyguard. Choso states that Okkotsu will be necessary to aid, especially against Kenjaku. Plus, Kenjaku's death means that his brothers and sisters will be freed. Tengen gives them an object, stating that it's the "back" of the Prison Realm. Before Kenjaku found it, the Prison Realm was outside of Tengen's barrier (possibly overseas). With the rear hidden, the front also essentially hidden but not for long.

Also, it's impossible to open the rear without the front, currently in Kenjaku's possession. Forced opening would require either the Inverted Spear of Heaven to nullify or the Black Rope to disrupt the technique. Both of which have been disposed of by Gojo, angering both Yuji and Megumi. Okkotsu remarks that he was searching for the Black Rope with Miguel but it ended with no success. Tengen states that a player named Hana Kurusu will be participating and her cursed technique can extinguish a cursed technique.

Locations

 * Tokyo Jujutsu High

Jujutsu
Cursed Tools
 * Inverted Spear of Heaven
 * Black Rope

Cursed Objects
 * Prison Realm