The Sea of the Elements - sometimes also called Elemental Sea or Sea of Elements - is the magic between the islands of Eo caused by the uproar of the primal elements during the Convocation. Because the circle mages called upon the elements when the dark roamer clouded the eye of Aonir, the power of the forces of nature, broke the very fabric of the world made by the All-Father.
This sea is not like normal ones because it is of magic origin and no normal ship is able to traverse through those lands. The elemental sea is lethal to anyone attempting to come into contact with it. The only known ways of getting past the seas is by using portal magic, by using the City Ship of the Shapers or by flying over the vast sea like the dragons.