Balion, like Geroia, is a region mentioned as existing outside of Calradia. Specifically, it is stated to exist across the expansive western ocean, refering specifically to Warband, as it is first mentioned as being the homeland of Konrad. In his biography, it is implied to be connected to Calradia through a shipping route.
Only mentioned in reference to Konrad, it is completely absent from the campaign. Thus, it is unknown if it will be revived in later installments.
It may be the ingame equivalent of England. Balion is an anagram of "Albion", a name sometimes refering to England, as well as being across a western sea just like England is across the British Channel and the North Sea from mainland Europe. Also, England has no equivalent in Calradia, as it would have a western european design, looking much like the Kingdom of Swadia or the Kingdom of Rhodoks, but with their famous longbowmen. However Balion is much farther away from Calradia, than England is from Europe.