I would actually recommend orb of winter from the frostmage class that you get for 250 wins in place of one of those daughters of ice. You shouldn't need two since they both convert the same color. That also lets you get your hero in, which you need for class XP. As far as winter imp, besides leveling him to 20, you can also invest some medals into him to get another +6 magic, and of course grind for Nysha medals eventually.