Your ranged unit, specialized for hit and run tactics. It's usually not helpful in matches where the opponent rushes you, but you always want at least one if they're playing a keep away strategy. One is often enough, as it should be kept safe and hidden, ideally in the one safe spot available. But don't be afraid to cast more copies in range intensive match.
When used well, it provides crucial reach for a faction that otherwise lacks it. However, given its cost, don’t summon one unless you have a solid plan to protect it.
In general, this is the first common you’ll consider discarding for magic.