Baby-faced Damien Darhk was a mysterious, elusive and dangerous figure. He claimed to be a major player in America's underworld and certainly had some connection to criminal organization H.I.V.E. He also seemed to have had access to unique high tech equipment that has never been used by any known organization. Darhk was considered a major criminal by the CIA and the FBI. However, their investigations revealed no hard evidence against him. He was a wi-fi fiend, staying in touch with associates by the very latest forms of mass communication.
What particularly baffled investigators was his apparent youth. Darhk seemed to be only in his early 20's, but already he was well established and connected. While opposing one incarnation of the Teen Titans, Darhk was stabbed and killed by Lady Vic, but his blood mingled with H.I.V.E. Mistress Adeline Kane, leaving himself immortal.
In Other Media
In the show Damien is not much at all like his comic book counterpart, save for the fact that he has affiliation with H.I.V.E., where in this case he runs the organization. Damien was also a member of the League of Assassins, an heir to the demon and the best friend of Ra's al Ghul.
After Damien left the League he seemed to have developed an interest in sorcery and the dark arts. He became such a powerful sorcerer that even John Constantine was frightened at the thought of facing Damien.