Impossible, Mage - No unit loss.

[Vilk]

Lol I agree it's hard to unsure no Cursed Ghost lost in all fights even if minimal. It's much more easy to ensure your cursed ghosts will do no damages to your own troops. I bet you under evaluate this point because you didn't use them enough.

But without Sacrifice you'll suffer with your horses when you'll won't have anymore enough of them. The penalty of a weaker stack will become more and more a problem and apart cursed ghosts I don't see anything to replace them until later in the game.

But ok use them will certainly be quite rude anyway for a no loss.