John Constantine is a DC comics character.
An antihero , or antiheroine , is a protagonist who lacks conventional heroic qualities such as idealism , courage , or morality . Constantine is an American television series developed by Daniel Cerone and David S. Goyer for NBC , featuring the DC Comics character John Constantine . John Constantine . He serves as the lead character of the comic books Hellblazer ( 1988 -- 2013 ) , Constantine ( 2013 -- 15 ) , Constantine : The Hellblazer ( 2015 -- 16 ) , and The Hellblazer ( 2016 -- ) . A live-action film was released in 2005 entitled Constantine , in which an Americanized version of the character is played by actor Keanu Reeves .