Oa is a fictional planet located at the center of the in Sector 0. History One of the oldest planets, Oa serves as the home and headquarters to a race of blue-skinned powerful humanoids who have dubbed themselves the Guardians of the Universe. The Guardians administer the Green Lantern Corps, a group of powerful universal police officers equipped by the Guardians with green-colored rings of power -- plus green lanterns with which to charge the rings. According to the story "Heart of A Star" in the Sandman: Endless Nights graphic novel, Oa's star is called Sto-Oa (the Light of Oa) by the children of the planet's inhabitants. Its location has been firmly established by numerous references in Green Lantern comics over the years. Oa's history is not clear; according to some stories, the Guardians originated in a planet called Maltus. These evolved Maltusians later moved to Oa and named themselves Oans. Oa became a co