The Celadon Sea was a deadly mist that blanketed the frigid mountain chains of the world Carnelion IV. Grecker, an agent of the Closed, held the Open responsible for the devastation of their planet and the subsequent creation of the Celadon Sea. During 29 BBY, Obi-Wan Kenobi, a Jedi Knight, along with his Padawan, Anakin Skywalker, experienced a crash landing within the Celadon Sea while responding to a distress signal. Beneath this toxic sea lay "The World That Was," which were the remnants of a sophisticated society annihilated by conflict between the Open and the Closed. Without breath masks for protection, the human inhabitants of the planet were mutated into creatures referred to as Fishers, who dwelled within the destroyed city. This forced the remaining survivors to seek shelter in the icy mountains above the Sea.