This article is settled on Earth 5.1, a technological and updated version of Earth.
Okarian Empire was a powerful empire with headquarters in Oka Star. It had power over 600 solar systems. However, its power became its doom, as they thought they can win a war against the other 3 stellar countries at the same time. It was not just stupid but it meant the total destruction of the planets of Oka Star. After a successful Great Okarian Offensive of Winter, the armies of Okarian Empire were defeated in the triple battle of Istara Group and Camusa Alpha. It lead to the Counter Offensive of Summer, were the Empire was totally destroyed as direct consequence of the great losses that the army suffered during the triple battle of Istara Group and Camusa Alpha (90 000 Okarian ships were captured, and 35 000 ships were destroyed).
Nowadays, 30 solar system have not surrender yet before the joint Pluto and allies/Kingdom of Dimmin army. They fight each other demanding to be recognized as true succesors of the Okarian Empire.