The Balta Family Cross.
The Balta Kingdom, formerly the Balta Pirate Guild, is now part of the Pirate Nation formed from the unification of former pirate guilds.
History
It seems the Balta family were originally citizens of Jurai who split away from the empire to become an independent pirate guild. It held some significant power as a pirate guild but a couple hundred years ago it was seemingly destroyed and Commander Balta was presumed killed. After his loss, the rest of the family disappeared and former pirate members of the guild took the Balta name as their own, to honor them, band together as a new group, and to gain the prestige of the once great pirate organization.
Eventually, the Commander's great-granddaughter, Ryoko Balta, was born. Her parents were killed and she was raised to be a pirate captain by their friend, her eventual adjunct and second in command. He knew her true identity as a genuine member of the Balta family but kept it a secret so others would not try to use her. Ryoko met her great-grandfather on Jurai, where he and some of the remnants of the earlier guild were hiding and reorganizing.
They were recognized as an autonomous group in Jurai and were stabilizing their new Kingdom, with the former pirate commander becoming their king, King Balta. Ryoko Balta becoming the princess of the kingdom. For now, she is declining her place in their royal court so that she can stay with Seina Yamada, her eventual husband, technically also making him a prince of the kingdom.
There was a plan to unite the shattered factions of the pirate guilds after the defeat of the Daluma Guid and assimilate them into The Balta Kingdom but it failed because the remaining leaders did not want to answer to another group. So the proxy war was created to resolve the issue instead, as told in Paradise War. In the proxy war to determine the leaders of the new nation, Alea Balta was its representative.