This game forces you to change your strategy!

[Kolorabi]

I discovered the phantom image spell yesterday, and have been using it heavily ever since. I've mainly used it on my griffins (also very good movement, and extremely good initiative, meaning they're almost always the first unit to move on the battlefield), and in addition to extra damage, there are basically two very nice things that I accomplish with it.

First, I put the phantom units in harm's way, and make them more tempting targets for the enemies. They disappear anyway, and each phantom unit killed is a real unit saved from death. Second, I use them as to attack targets that have dangerous retaliation strikes. When they've retaliated on my phantom units, I bring in my real units to hit them hard, without fear of retaliation.