Created by Bob Haney and Lee Elias, the character would first appear in House of Secrets #61 (August, 1963).

Throughout Eclipso's history, the character is frequently depicted as an adversary of the Justice League, its affiliated teams, and Amethyst, Princess of Gemworld.

Eclipso appeared as the main antagonist of the second season of The CW television show Stargirl, portrayed as an adult by Nick E. Tarabay and Jason Davis and as a young boy by Milo Stein.

[1][2] Originally, Eclipso was written as a generic villain who would routinely enact an elaborate plot to fulfill his hedonistic motivations.

Eclipso would frequently seek to possess beings of incredible power like Superman, Lar Gand, and Captain Marvel to achieve his ends.

[4] During this period, Eclipso was portrayed as a conventional villain, possessing super strength, partial invulnerability, and optic blasts.

Any bright flash of light would banish Eclipso back into Bruce Gordon's body or reverse the change.

In issue #13 of the series, Eclipso defeated them, killing Wildcat II, the second Doctor Mid-Nite, the Creeper, Commander Steel, the Manhunter IV (a Mark Shaw ringer), and Major Victory.

The survivors arrived in the United Nations building, just in time to foil another plot of Eclipso by landing their vehicle on his intended victim.

Bruce Gordon and Mona Bennet led Earth's superheroes in an attack on Parador, in an attempt to destroy Eclipso once and for all.

In a Biblical context, Eclipso was responsible for Noah's Flood, while the Spectre was the Angel of Death who slew the first-born Egyptian children.

The Spectre destroys the Heart of Darkness, along with the remains of Eclipso's palace on the moon, burning them and casting the ashes into outer space.

Eclipso returns after several years' absence in the "Princes of Darkness" storyline in JSA as an ally of Mordru and Obsidian.

[6][7] Captain Marvel exploits Superman's weakness to magic to defeat him and recruits the Spectre to exorcise him.

[1] In Countdown to Mystery, Eclipso corrupts the heroes Plastic Man, the Creeper, and Dove and reassembles the Heart of Darkness.

[18] Eclipso possesses Lord before Killer Frost uses her powers to create a prism, trapping him in the Black Diamond.

The character can also alter their size, growing to giant proportions, has the ability to emit deadly rays of dark light from his left eye and a powerful burst of paralyzing black light from his right eye by looking through a shard of the Heart of Darkness gem.

Furthermore, Eclipso has demonstrated the ability to absorb the powers of the Spectre and project potent energy from their hands, capable of stunning or even killing adversaries.

Having once served God, Eclipso possesses the ability to communicate in the angelic language, which encompasses elements of harmony, discordance, vibration, and telepathy.

Once overshadowed, Eclipso controls the host's powers, manipulates their behavior, and alters their memories to serve his own purposes.