The Quest for Truth

I continued playing the third game. I don't know if this is a bug, but the elementals of the main villain appear after the death of his units, but only in battles against Sandro. At first, I struggled with these elementals, then I decided to spread out my army with ordinary Necromancers, and I was a little surprised. I took Lucretia and continued to be pleasantly surprised. Unfortunately, I wasted a lot of time - with Lucretia and without the elementals, I could have defeated him without all the fuss. Is that how it's supposed to be?