Located within Hydrus' asteroid belt, Asselio Ridge was a strategically vital region in the system. At this stage, the UNIA was beginning to degrade, so they were under pressure to bring the war to a close. In 2519, they would launch a massive offensive against Gauusian forces in Asselio. While it didn't necessarily catch Gauus by surprise, it did overwhelm them to the point where they were outmaneuvered in the field. This would be their most catastrophic defeat, as much of their fleet would be destroyed in the assault. Their resource routes would be compromised as well, with the UNIA quickly taking control of them shortly after the Asselio Ridge assault.

Following this defeat, Gauus wouid be unable to mount a significant resistance, bringing the war into it's final stages.