The Sea of a Thousand Souls is the body of water that lies to the southeast of the Continent, a roiling ocean that is nearly impossible to survive on the surface, not that it's much better down below. There are constant storms and hurricanes and whirlpools, with barely a hint of good weather to be seen. The Sea of a Thousand Souls is also the natural habitat and breeding grounds of the Leviathans, a beyond average concentration of them which makes sailing any sort of fleet through the sea a deadly risk. While you could technically survive and sail to the other side, no one has managed to do so, not while remaining in one piece.