by DC Within this series it was retconned that Eclipso was not simply Bruce Gordon's dark half, but a vengeance demon who had possessed Gordon.
After an unsuspecting Daxamite hero named Valor frees Eclipso from his palace on Earth's moon, he uses hate as a trigger to possess other beings. Whenever someone who has a black diamond in their possession gets angry, Eclipso can instantly take control of that particular person even while trapped in his lair on the moon. He then uses an eyeblast to take control of others. He can also create monsters from a person's anger, which happens with characters like Hawkman and James Gordon. Furthermore, there are thousands of black diamonds scattered around the world, through which Eclipso can possess his victims by playing upon their darkest emotions and desires.
It is further established that Eclipso is an extremely cruel and vindictive being, who has only been pretending to be a B-list villain in order to avoid detection by heroes.