Fortress vs. Necropolis

I was playing as the Tower faction, leveling up the Summoning skill, and chose the "Elemental Equilibrium" perk. When the opponent, playing as Necropolis, cast Necromantic spells (Berserker and others), I decided to summon a Phoenix to help. I was very surprised to see that another Phoenix appeared on the other side, but with a higher attack value for the Haven faction. With this Phoenix, I quickly decimated the Vampire and Zombie units. His Phoenix was eventually defeated, but with significant losses on my side. However, the opponent was distracted by the Phoenix, and in that moment, I cast Divine Shield on my Hydras and sent them into battle. His Berserker couldn't help, as the Hydras managed to get close to his units, and then I cast "Wrath" on them with ten Shadow Lords. It killed the enemy, but my Hydras were almost wiped out. Against undead, level up Summoning for the late game; it helps.