Darkseid is a villain from the DC Universe and the ruler of the desolate planet Apokolips. As a "New God", the rock-like villain Darkseid is an immortal who seeks to end all life in the Universe with an "anti-life" equation. Primarily, Darkseid serves as an antagonist to Superman whose first full appearance was in Forever People #1.
Darkseid was not always the rock-like menace that he is today. Darkseid was born Uxas and he was a Prince on a hellish planet named Apokolips. Uxas had an older brother, named Drax, who was first in line for the throne... but Uxas was hungry for power. When a connection to the Omega Realm was discovered, Drax was intended to merge with it and claim his power. Before Drax could claim the "Omega Force", Uxas murdered him and claimed the power for himself. The Omega Force turned Uxas into Darkseid- a rock-like villain of incomparable power.
Darkseid wages a war on Apololips' sister planet, New Genesis. He kills as many other "New Gods" as he can just for fun. When he encounters green martians he learns of their belief in a force called "the will" which they believe represents the "life equation". As a walking embodiment of hate, Darkseid theorizes that there must be an equal (but opposite) equation, an "anti-life equation", that would wipe out life as we know it. He spends his life searching for the "anti-life equation" and comes to earth upon hearing rumors of its existence.
In recent stories, Darkseid meets his end in The Justice League #44 and his power is transferred to Lex Luthor.
More origin information can be found in The New Gods #1