The Union of Anea is the temporary nation formed out of the coup d'etat that joined all the nations of Anea together against the Osean Federation. They were the primary enemy during the Anean Uprising.
The Union of Anea was formed by certain military officials from each nation of Anea working together to build Aumaan. Together they staged a coup d'etat and somehow brought down the governments of all three nations in one fell swoop, before completing Aumaan. The nation wasn't officially announced until war was declared against Osea, signaling the start of the Anean Uprising.