Why is Shuichi immune to spiral?

Shuichi Saito was one of the first people to witness the effects of spiral in the story. He wasn’t immune to its influences, however, he may have been one of the first ones to have been infected.

The manga series Uzumaki by Junji Ito is a psychological horror story. The characters in the novel are Kirie Goshima, a high school student, Suichi Saito, her boyfriend, and the people living in Kurouzu-cho, a fictitious town in Japan. The town's residents are said to be impacted by an unexplained force called the spiral that plagues the region. Either they become fixated on the spiral or resent its implications.

Shuichi Saito’s life in Uzumaki

As the story goes on, Kirie and Shuichi see directly how the spiral curse impacts those in close vicinity, turning them into either spiral-obsessed or spiral-paranoid people. After both of his parents perish from the terrible psychological and physical effects of the spirals, Shuichi withdraws into himself. He acquires the ability to recognize when the spiral curse happens, but this skill is commonly ignored until the curse's subsequent paranormal repercussions become evident.

The town continues to be ravaged by the curse until a series of typhoons caused by the curse destroy the majority of the town's buildings. The residents are forced to live in the old, abandoned terraced houses that are the only structures left, and as they get increasingly crowded, they start to spread. Kirie and Shuichi come up with a plan to flee Kurouzu-Cho as a series of severe storms and further damage caused by criminals who can use strong winds hit the town, but their attempts to flee prove fruitless.

What happens to Shuichi at the end of Uzumaki?

As time speeds up away from the spiral, they return to the town and find that several years have passed since they left. The other residents grew the terraced buildings until they united into a single building that formed a maze-like spiral design, but as a result of the crowding, their limbs began to twist and distort into spirals. After exploring the maze for several days, Kirie and Shuichi arrive at the centre when they decide to look for Kirie's parents.

A deformed resident at the center tosses Shuichi down a pit that descends far beneath the surface of the earth, and Kirie descends a massive spiral staircase to find him. She stumbles and is rescued by several corpses that cover the floor of an enormous, old town made up solely of spiral patterns arranged in different configurations. Kirie discovers her parents and numerous other Kurouzu-Cho residents who have suffered the same fate as she searches for Shuichi. They are both twisted and petrified, looking like stone statues.

She then goes to Shuichi after hearing him call for her. Shuichi hypothesizes that the spiral city, which is facing the terrified residents of Kurouzu-Cho, is the origin of the curse. The city grows on its own every so often and has cursed the area above out of envy that no one is around to see it.

What is Shuichi and Kirie’s fate in the City of Spirals?

Kirie responds that she lacks the strength and wants to stay with him, but Shuichi begs her to leave without him as he is no longer able to walk and the curse should end soon. As a symbol of their acceptance into the never-ending curse, the two embrace, their bodies twisting and tying.

Kirie notes that the curse stopped at the same moment as it started while Shuichi and she lie together because time freezes at the center and accelerates up in the opposite direction. Given the spiral's eternal curse, when a new Kurouzu-Cho is constructed where the old one was, everything that happened will happen again.