What of those who wish to risk delving under the ice, despite the freezing cold and ease of getting lost? Is there anything that can aide them?
A set of rings, useless above the ice where there's no enough active ambient magic to feed their enchantments, but if one can survive the passage into the frigid waters, down over a hundred through glacial ice, and then last a minute more for them to charge, they become far more handy. One to let the wearer breathe beneath the waves that once were, another to keep them warm against the cold (although it strains, so cold is the Sea, to do what it does), a third to let the wearer see by sound, and a fourth to give a merfolk's fabled tail and the instinct to swim.