Green Lantern Corps

After the failures of the Psion and Manhunter projects, the Guardians of the Universe decided to use living agents as their intermediaries, to overcome the forces of evil and injustice.

- History of the DC Universe #1

Three billion years ago, a group was formed and supplied with the energy pistols and power batteries similar to the Manhunters. This group was the immediate predecessors of the Green Lantern Corps. - Green Lantern Vol. 2 #90

The Guardians then developed a device in the shape of a ring that could channel will power. There were some limitations imposed on the power rings. They would need to be recharged every 24 hours, and there was a yellow impurity. This has been argued as a neccesity to fix the energy admixture (the Guardians' power to be adapted to individual ring bearers) and/or as a safety device to prevent any of the Green Lanterns from becoming omnipotent. It is believed by some Green Lanterns that this limitation actually strenghtens them by foring themselves to take nothing for granted.

Rori Dag of Rojira was selected by the Guardians to be the first Green Lantern. His success marked the beginning of the Green Lantern Corps. Each Guardian selected one species to have a Green Lantern as a representative. - Green Lantern Vol. 2 #67, Green Lantern Vol. 2 #40

The known universe was divided into 3600 individual sectors, imaginary pyramids with their points converging on Oa, making the Guardians' world the best protected planet in the universe. - Green Lantern: Ganthet's Tale

The Corps was shattered by Hal Jordan when he was controlled by Parallax. The last power ring, created by Ganthet, was given to Kyle Rayner. - Green Lantern Vol. 3 #50

Years later, when Jordan was freed of the control of Parallax, the Guardians of the Universe restored and expanded the Green Lantern Corps. To better combat the growing threats the future would hold, 7200 Lanterns would patrol the stars. GREEN LANTERN CORPS: RECHARGE

Recently, the Green Lantern Corps has battled the yellow ring wielding Sinestro Corps preceding the War of Light. Utilizing the energy of the emotional spectrum, other forces have arisen; the Red Lantern Corps, Larfleeze and his Orange Lanterns, the Blue Lantern Corps, the Indigo Tribe, and the violet energy Star Sapphires. This in turn led to the rise of Nekron and his Black Lantern Corps. The Green Lanterns and the other Corps found themselves at times in unlikely alliances until Nekron was ultimately defeated.