[Festin]

Well, I found Adepts of Silver Order, so Air was easier for me.

But Hidden in the Snow is a really great spell, especially for Ermor. It is easily castable, not very expensive (W gems do not have many uses), gives a mage with D/E/W, a thuggable commander (slightly better than Bane, if I remember correctly), and a bunch of quite durable undead, who are not mindless and so are good for castle defense. Neat.