Necromancer – “Ruler of Erathia” [Campaign 3, Mission 5]

I killed Godric very easily, practically without using any mana. It's very simple: cast Mass Plague on the enemies in the city and just defend with all your troops. The towers and all enemy archers will attack our skeletal archers, of which we have about 100-150. These archers will hold out for a couple of turns, and while they're alive, we infect another part of the enemy troops with the plague (it doesn't affect gargoyles, so we'll have to finish them off with troops at the end of the battle). As soon as our archers are killed, we use "Raise Dead" on them, and they continue to absorb almost all of the enemy damage. The entire battle proceeds like this: we just defend and spread the plague. If all the enemies are already infected with the plague, then we can hit them with lightning or something else that doesn't consume much mana. I don't recommend using Mind Control, as it consumes too much mana and is not very effective in terms of damage. By the end of the battle, mana will be running out, so to regenerate it, we cast "Necromancer's Sign" (restores our mana when a creature takes damage) on our archers or on those who are frequently attacked.