"The Will of Ashan" - "Heart of Darkness" [2nd campaign, 5th mission]

Lord, a Necromancer never runs out of mana because of the Necromancer's mark. When I stormed a castle with a huge number of Cyclops, the Avatar was killed many times. There were almost no mana problems because of this. There was enough mana to summon a new Avatar and a Phoenix. The Cyclops stood in the gate, and the Avatar and Phoenix blocked their path to my troops with their bodies.