“Treacherous primeval dragons of the northern regions of the world” says the Bestiary 3 of linnorms, and ice linnorms double down on the northern aspect. Thanks to its breath weapon, freezing bite, and death curse, an ice linnorm is cold personified, with a cruel streak to match.
The herders of Mindar speak of the lentävää poroa—the reindeer pegasi that dot Mindar’s shimmering boreal skies. They also speak of Glacierbite, the ice linnorm who delights in blasting the magical beasts from the sky with his frigid breath, cackling as they shatter on the rocks below.
Where the tundra and the taiga meets, so too do the territories of ice linnorms and taiga linnorms. Should these titanic beasts encounter each other, the result can range from cold condescension to cutting insults to all-out bloodbaths. The exception is when the full moon and the winter solstice coincide. Then, according to a few scattered reports, ice and taiga linnorms engage in sinuous, strangely beautiful dances that conclude in the ritual exchange of treasure. The reports are unreliable because of another strange custom: the linnorms do not mind witnesses to the dance, but they vigorously hunt down and kill anyone who speaks of what they saw, or who attempts to help him or herself to the proffered piles of gold.
That linnorms speak Draconic and Sylvan makes sense—these are creatures with ties to both so-called “true dragons” and the lands of the fey. That they speak Aklo, though, is surprising—while linnorms do lair in caverns, they rarely haunt the deep reaches where the aberrant tongue is favored. But linnorms as a race remember previous ages and even other realities, when the dragons and fey had only just inherited the world from aboleths, ropers, and worse. And ice linnorms in particular dwell in mountaintop and polar regions where the air is thin and the boundaries between dimensions even thinner. An ice linnorm may be able to tell you more about Leng or the Realm of Dreams than any dragon has a right to know—if it doesn’t kill you for disturbing its already fitful, nightmare-wracked slumber.
—Pathfinder Bestiary 191
Forgive me if you’re from Finland and I’ve butchered your language; I used FreeTranslation.com to make my best guess.