Orson with defense, 600-700 zombies (around month 3) with artifacts (mana around 250-270) and Berserk/Subdue/Vampirism/Heavenly Shield/Clones/Crystal skills destroys everything (+mass Darkness spell). Banshee Scream, -2 to luck or spirit ring (black dragon gives -1 to morale). Grief -5 to luck/morale. This all helps a lot (especially if the Necromancer didn't use his army from the castle at all, but only brought them to the final battle). Level is approximately 20-24. There's no point in leveling up further.
Orson with defense, 600-700 zombies (around month 3) with artifacts (mana around 250-270) and Berserk/Subdue/Vampirism/Heavenly Shield/Clones/Crystal skills destroys everything (+mass Darkness spell). Banshee Scream, -2 to luck or spirit ring (black dragon gives -1 to morale). Grief -5 to luck/morale. This all helps a lot (especially if the Necromancer didn't use his army from the castle at all, but only brought them to the final battle). Level is approximately 20-24. There's no point in leveling up further.