Organization for General Revenge and Enslavement
The first O.G.R.E. was a small "mercenary terrorist group". They were led by a guy in a black hood called Supreme One, who led a group of foot soldiers with red helmets and brown uniforms. They were hired to steal some nukes. Aquaman and Mera interfered with this plan and convinced two agents Huntress and Typhoon (who were working for the group, because O.G.R.E. threaten to kill them) to turn on O.G.R.E., who they defeated. Months later, a guy named Krako re-organized the group. He threatened the UN, but was defeated by Aquaman. He tried (and failed) to bomb Atlantis, while Black Manta distracted Aquaman. However, the government located and destroyed their HQ.
Ocean Going Research Exchange
A second O.G.R.E. was formed, but it doesn't seem to have ties to the original one. It's also simply called the Exchange. Founded by Jordan Wylie (the CEO of Merrevale Oil), it tried to discredit the Sea Devils' environmental actives and had hostile encounters with Aquaman. Aquaman accused Jordan of ruining the environment, resulting in Jordan losing his job. O.G.R.E. decided to make Jordan "less visible".
Ocean Going Research Exchange
A second O.G.R.E. was formed, but it doesn't seem to have ties to the original one. It's also simply called the Exchange. Founded by Jordan Wylie (the CEO of Merrevale Oil), it tried to discredit the Sea Devils' environmental actives and had hostile encounters with Aquaman. Aquaman accused Jordan of ruining the environment, resulting in Jordan losing his job. O.G.R.E. decided to make Jordan "less visible".
References:
http://en.wikipedia.org/wiki/O.R.G.E._(comics)
