The Leviathan

Leviathan worshipers worship the return of the great leviathan to return the Hazfen desert back into the great dawn sea. 
The Leviathans depictions in Locathan art depict a massive fish always many times the size of the other drawings around it. Easily a gargantuan class creature, no further details are known about its appearance.  Outside scholars know of some writings of a monster that would have the power to alter an entire region but its writings are around the time of Thánatos "The Destroyer"  Common consensus is that the leviathan was just Thánatos "The Destroyer" , but there are some who believe it is a separate entity.