Parasite Eve is a Japanese novel by Hideaki Sena, first published in Kadokawa Horror Bunko. It was later adapted into a film in 1997, with a heavier focus on romance than horror. In 1998, the video game was released for the Sony PlayStation by Squaresoft, now known as Square Enix, as the sequel to the novel. A sequel to the game was released in 1999, also for the PlayStation. To continue with the idea of the manga for the video game, a manga was produced of the novel to tell the events for those gamers who had not read the novel.