The Ophidians were a race of humanoid snake-like creatures that lived on Earth thousands of years ago.
The Ophidians, snakes who walked like men, fought mankind over domination of the planet. They worshiped the moon and preferred the dark over the light.
Mankind was winning the battle, and eventually drove the Ophidians to near-extinction. In desperation, the last remaining Ophidians performed an arcane ceremony during a lunar eclipse, sending their souls into a dark gem later dubbed the Heart of Darkness. Anyone who held the crystal would become possessed by the Ophidians' spirits and driven to destroy mankind. Mophir's people dedicated their lives to guard the crystal from falling into the wrong hands.
After a failed attempt to manipulate the Justice League into extinguishing the sun with an Anti-Fusion Device, the Heart of Darkness was destroyed and the Ophidians' souls expunged from the League. The remaining shards presumably contained the reptilian creatures' spirits, but it is likely that they were confiscated and stored away by the superhero team in order to prevent anyone else from falling under the Ophidians' vengeful enchantment.