Princess Louvia's room in the Phantom Ship, also named Saint Louvia
Princess Louvia was Shana's twin sister. Being the daughters of Queen Theresa, Louvia and Shana were princesses of Mille Seseau.
When the new Moon Child was born, the Black Monster attacked Mille Seseau, searching for the Moon Child. The baby Shana somehow got lost when they passed through Neet, while the baby Princess Louvia was placed on a ship called the "Saint Louvia".
The Black Monster still tracked down the Saint Louvia, presuming Louvia was indeed the Moon Child. The Black Monster killed Louvia and all the knights and members on the ship.
Unearthly powers enabled the ship, with tattered sails and a literal skeleton crew, to continue its ghostly voyage as the Phantom Ship until the events of The Legend of Dragoon.