John Constantine is a fictional character.
John Constantine ( [ ˈkɒnstəntaɪn ] ) is a fictional antihero , appearing in comic books published by DC Comics and the DC Comics imprint Vertigo . Welsh actor Matt Ryan was cast in the role of Constantine for the 2014 NBC television series Constantine , a role he reprised on The CW series Arrow , the animated film Justice League Dark and is set to reprise again in an upcoming animated continuation of his series on CW Seed .