Necropolis or Castle (Which one is stronger?)

To defeat Necropolis with human units, you need tactics, leadership, Earth Mastery, and Air Mastery skills, and Water Mastery would also be helpful. Use tactics to protect your archers and move your crusaders forward. Then, either cast Slow on the Necropolis units or Prayer on your own (or Haste). And attack the liches and vampires first.