Eclipso: The Darkness Within is a 1992 comic book miniseries and crossover storyline published by DC Comics. It featured the heroes of the DC Universe fighting against Eclipso. Issue #1 debuted July 1992, and was created and co-plotted by Robert Loren Fleming and Keith Giffen. Keith Giffen also did pencil layouts for the series, and Bart Sears provided the finished artwork.
History
Within this series it was retconned that Eclipso was not simply Bruce Gordon's dark half, but a vengeance demon who had possessed Gordon.
Plot
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.