In 3285 L.Y., a small moon was discovered that had abundant resources and a strategic location. This moon was soon named Lex. The first settlers of this moon founded a thriving colony, and there was peace for a very long time. Suddenly, the peaceful life of the colony was shattered when half of the populace split off and tried to take over Lex for greedy purposes. Lex's capital city, Vestas, was almost lost in the uprising. As a result, economical and political upheaval was widespread. The population of the moon was split into two territories, the remaining peace-supporting minifigs forming the Lex Democratic Coaliton (LDC). The minifigs who had rebelled formed the Lex Imperial Army (LIA). With assistance from the Nihilith Army, the greedy and corrupt LIA was defeated by the LDC and peace returned. And, just after the Lex Civil War ended, UOA was created to govern the moon. A military organization, its purpose was to make sure that peace would stay on the moon of Lex. The UOA has defended Lex from many attempts of invasion by various factions to this day. UOA has also joined the UNE in their ongoing struggle with the COP.
Now, larger than ever before and equipped with some of the most advanced military technology in the MOC universe, UOA has taken up the role of peacekeeping and armed intervention across the MOC universe. UOA currently has 50 000 enlisted personnel and staff.