Oa

Oa is one of the oldest planets and serves as the home and headquarters to a race of blue-skinned powerful humanoids who have dubbed themselves the Guardians of the Universe who administer the Green Lantern Corps. Oa's star is called Sto-Oa (the Light of Oa) by the children of the planets inhabitants.

Oa's history is not clear; according to some stories, the Guardians originated in a planet called Maltus and then moved to Oa as a convenient base of operations. Other stories had the Oans living in there from the beginning.

Oa appears to be mainly a desert-like, lifeless planet. The main feature is the Guardian's city, which includes, among other things, the Main Power Battery that is charged by the Guardians with their own unique green energy, which the Battery then broadcasts to the personal Power Batteries of all the Green Lanterns.

At one time, Oa was host to several cities stolen from various worlds (including one from Earth) along with their unwilling inhabitants. This "mosaic" of cities was created by an insane Guardian who was left behind when the others left the universe for a time. Although he was defeated by the Green Lanterns, when the Guardians returned, they decided to keep the cities on Oa as an experiment in multicultural cohabitation. This decision was against many of the inhabitants' wishes to be returned to their home worlds, and was looked upon unfavorably by many Green Lanterns (but respected). The Green Lantern John Stewart was assigned to keep peace in the composite city.

Oa was eventually left uninhabited after the Green Lantern Hal Jordan, under the influence of the evil entity Parallax, killed all but one of the Guardians and most of the Corps. Later it was destroyed in a battle between the still-insane Jordan and his successor, Kyle Rayner.

The planet was reformed sometime later by Jordan's old friend and associate Tom Kalmaku. The Central Power Battery was then recharged and the Guardians resurrected shortly therafter by Kyle Rayner after he spent some time as the near-omnipotent "Ion".

After attacks by Superboy-Prime and the Spider Guild, the Guardians refortified Oa by creating a planetwide armour and defensive system to prevent successful attacks against them. The full capability of the new systems are still unknown.