Gantz (Japanese: ガンツ Hepburn: Gantsu) is a Japanese manga series written and illustrated by Hiroya Oku. Gantz tells the story of Kei Kurono and Masaru Kato, both of whom died in a train accident and become part of a semi-posthumous “game” in which they and several other recently deceased people are forced to hunt down and kill aliens armed with a handful of futuristic items, equipment, and weaponry. Both the manga and anime are noted for their heavy violence and sexual content.Gantz tells the story of a teenager named Kei Kurono, among others, who die but find themselves brought back in perfectly healthy bodies and forced to participate in a “game” where they must hunt down and kill aliens. Those who die on missions are quickly replaced by others in the following missions. The series is known for its graphic violence, sex, action, and similar mature themes. It has sold at least 19 million copies so far. The Gantz anime adaptation, directed by Ichiro Itano and animated by Gonzo, contains 26 episodes divided into two seasons. A series of two live-action movies based on the manga was produced and released in January and April 2011. A CGI anime film, Gantz: O, was released in 2016.