Levyssal was a legendary cetacean CEI (Cryptofauna of Exceptional Interest) in the Verdant Sea and was a major figure in Zhāngian culture. The creature was supposedly between 50 and 150 meters in length, weighing 333 to 1000 tons. Levyssal was described to have a serpent like body with two elongated pectoral flippers, two hind flippers, three fins at the face, and bioluminescent stripes. 

Levyssal was presumed to feed off smaller cetaceans and large fish, with some marine carcasses documented with unusual and abnormal damage, but the exact cause was left undetermined. Similarly, many ships went missing or wrecked over the course of history, but once again with no determined cause. 

The Zhāng believed the bones and especially the teeth of Levyssal held exceptional medicinal qualities. In the late 7th Age, bone fragments of a large marine animal began to wash up on the shores of Frauji, spared from the corrosive Venom Sea. Zhāng tribes collected and traded these worshiped materials, and one intrepid chieftain turned the tooth fragment he possessed into a hunting sword.