Eswen, officially known as the Republic of Eswen, was an island nation situated in Sera's equatorial region. Due to its location, with half of the nation on the equator, the island had varying climates and biomes, resulting in a jungle environment in the north and a more temperate southern region. During the Pendulum Wars, Eswen fought as part of the Union of Independent Republics where there impressive Navy defeated Coalition forces in several important battles. In 27 B.E., the COG launched a large-scale invasion of Eswen, utilizing Army, Navy, and Marine forces, fighting their way to the capital and forcing an Esweni surrender. The COG annexed the nation soon after, using it as a staging ground to launch further assaults in the region.