John Constantine is a fictional character.
An antihero , or antiheroine , is a protagonist who lacks conventional heroic qualities such as idealism , courage , or morality . These characters are usually considered `` conspicuously contrary to an archetypal hero '' . John Constantine ( [ ˈkɒnstəntaɪn ] ) is a fictional antihero , appearing in comic books published by DC Comics and the DC Comics imprint Vertigo . The Swamp Thing is a fictional character in the DC Universe .