Rumors circulating within the shadowy cantinas suggest that a significant battle from the era of the Galactic Civil War unfolded on the aquatic planet of Castilon, a world largely covered by ocean, around 4 ABY. This confrontation saw the forces of the New Republic clashing with those of the Galactic Empire, the latter deploying at least a single Star Destroyer. It is said that, amidst the conflict, the New Republic suffered the loss of a starship, which plunged into the depths of the ocean.
This particular battle received a mention in the video game Star Wars: Squadrons, released in 2020. Specifically, it appeared in the description associated with the "Castilon Dawn" cosmetic variant for flight helmets worn by New Republic pilots.