Avion Sea

Avion Sea is sea located somewhere in the Navy navy Special Region and far away from the reach of the Empire. The sea once ruled by the Avion dynasty who controlled a vast kingdom with dozens of islands. After the Avion dynasty declined, the Avion islands were separated into multiple kingdoms, which are: Tinae, Javiá, Ubulla, Manuham, Seiraf, Sarandip, Routerbagga, Shichijima while the remaining islands being controlled by pirates.
The Avion Sea is main focus in Gate: Weight Anchor.
The reason why the Empire never attempts to invade Avion Sea is because their Navy force is too primitive and inefficient.