NBC's adaptation of DC Comics' 'Hellblazer' stars Ryan, 33, as a dark magician who becomes humanity's last hope against conspiring dark forces, reported USA Today.
Ryan said that John Constantine is unlike fellow DC Comics heroes Superman, Wonder Woman and the Green Arrow.
"He's not a superhero with a cape, someone with a special power. He's just a working-class guy who uses cunning, wit and street charm to get what he wants," the actor said.
"His mission is to save humanity from the evil of the world and the good forces. He doesn't like either side interfering in humanity."