This article contains plot details from the latest book.
Frosters are a type of elves with the special ability of cryokinesis. This means that they can manipulate ice particles in the air to freeze whatever they want. In Book 1: Keeper, Dex and Marella were tested at Foxfire to see if they may be Frosters by sticking them in a very hot room for the whole period. Frosters can also cover themselves with ice as a disguise. This is seen in Neverseen (the book) when Squall, Juline, does it as her disquise. Dex describes Frosters as a useless ability, even though his won mother is one.