Yal Tengri also known as the Great ice Sea, is a southern extension of the northern ocean that covers the top of the world. Its waters are frigid and icebound in winter. The ocean is home to many cold-loving creatures, from the mundane to the dangerously exotic.
The Yal Tengri is free of ice for the six summer months of the year. In the spring, sailors must be watchful for icebergs that calve off the permanent ice cap further north. In the fall, there is the risk of becoming icebound as the waters gradually freeze over. By winter, the Yal Tengri is a sheet of ice with only a few open passages. These are treacherous routes, subject to the shifting winds and currents. The residents of Naupau are rumored to know the ways of the ice.