Istid

The once massive icy landscape of Istid has been engulfed by cold seas since the calamity known as the Great Deluge engulfed the human realms.
  Now, most of Istid is submerged either by the calm Varsemian Sea or the treacherous Sea of Stars.
  The pockets of land that survived the deluge are the icy fjords and have become home to the various folk.
  While there's barely any land bridge with the frozen wastelands of the north known as the Great Unknown, in colder seasons the sea freezes, making it possible for the savages of the North to come down upon the human realms.