Ustio

Ustio, officially known as the Republic of Ustio, is a small landlocked nation located on the Osean continent. It is bordered by Belka to the north; Recta and Ratio to the east;Sapin to the south; and Osea to the west. Ustio's capital,Directus, is situated near the center of the nation.

Formerly Belkan territory, Ustio seceded in May 1988 as a result of the former's ongoing economic crisis. The country appears to be largely agrarian, featuring rolling patchworks of farmland and remote towns, such as Solis Ortus, situated in the rugged mountain ranges. Ustio's northern regions are known to be rich in natural resources. As a fledgling nation, Ustio supports a modest military force, which has been known to employ mercenaries to bolster its numbers.

Ustio is the player character's employer in Ace Combat Zero: The Belkan War.

In When the Cold Breeze Blows Away, when the Belkan Grey Men and the Global Liberation Union attacked in Second Belkan War,Ustio has joined the Grand Alliance for counterattack.