Fire Magic should be immune to the hot temp in Ilmari, and get either a passive at a certain level that negates the temp reduction in Kur, or one of the spells like Molten Veins should reset the temp reduction bar.
Similarly, Ice Magic should be immune to the cold in Kur, and should either get a passive like above or an active spell that resets the temp in Ilmari.
The "Cold Protection" spells should be castable on others, as they seem silly for classes that can control fire and ice.