Black Paradox is a multi-chapter manga written by Junji Ito. It follows four people who meet for a group suicide, but their attempt to die instead makes them aware of a bizarre phenomenon that could change the world.
A young woman who works as a nurse. She is stricken by paranoia and premonitions of the future; she seeks to die so that she won't have to experience the horrific events she predicts.
A greedy man who became suicidal after meeting his doppelganger which he believed to be an omen of his forthcoming death, thus would rather take his own life than wait for death to claim him. He later becomes rich by exploiting Paradoxical Night.
A melancholy young man who was used as the model for a perfect humanoid robot. He could not compare to its perfection and thus felt that there was no reason for him to continue to exist. After taking an overdose of sleeping pills and his heart stopping, he witnesses the spirit world and begins to produce spirit jewels from his stomach via the pylorus - a word which, in Japanese, is written with the characters for "spirit" and "door."
A woman with a disfiguring birth mark covering one side of her face. She believed her reflection was coming to life and that this was foreshadowing that she would die. She has the spirit jewels valued and classified as a new kind of mineral, also putting them on sale under the name "Paradoxical Night."
A surgeon working at the same hospital as Marusou. He planned to treat Baracchi's birthmark. He found Piitan abandoned at the hospital and uncovered the truth about the spirit jewels, planning to use them as a sustainable energy resource. He is a manipulative liar who cheats people and seduces women easily.
The robot designed after Piitan's image. It is powered by Piitan's own soul inside one of the spirit jewels. Although initially perfect, it becomes suicidal like Piitan after being revived by the spirit energy. It can also be used to enter Piitan's portal and retrieve the spirit jewels from the other world.
An attractive actor of whom Baracchi was a fan. She sent him one of the spirit jewels, which he wanted to share with his fans; unable to break the jewel apart, he fired at it with a gun, causing an explosion of energy which killed him and everyone present.