Oa is the homeworld of the the Green Lantern Corps. It is also the secondary home of the Guardians of the Universe, who created the Corps with their own technology.
The Central Power Battery, which powers the other power batteries that every Corps member carries, is stationed here. Oa is also where Green Lantern recruits are trained by veterans of the Corps, like Kilowog and Sinestro before he left to form the Sinestro Corps.
Oa is seen several times throughout Year Two, particuraly chapters three and eight, which focuses on the Guardians discussing the events transpiring on Earth as well as being the planet the entire Green Lantern Corps is recalled too.
Role in Injustce
It is briefly seen in Green Lantern's super move and at the end of the story mode, where the main universe Hal Jordan brings his duplicate and Sinestro before the Guardians of the Universe.
- Oa appeared as a stage in the crossover game Mortal Kombat vs. DC Universe, though it has been relegated to a cameo appearance during Green Lantern's Super Move in Injustice: Gods Among Us.