Here's a fun example: troops with random upgrades, random secondary skills, and I set the mage to auto-battle. In the battle, I controlled the Necromancer because he's weaker. It resulted in an interesting fight:
Week of Light (-2 luck/morale for dark creatures)
Opponents:
Mage Faez, level 40 (9/8/31/38), army
* Ring of Speed 10%, Ring of Sinners, Bow, Dragon Crown, Mage Robe, Boots of 10% Resistance, Lion's Amulet, Necromancer's Cloak, Horseshoe
* Darkness, Chaos, Light (all additional skills - main ones), Defense (HP+2, general skill - leather armor, staunch defense), Education (Baldric + Magical Reward)
Useful spells: general (weakness, slow, magic bolt, vulnerability, haste, stone skin, dispel, dodge), antimagic, vengeance, berserk, blindness, cold.
Necromancer Raven, level 40 (14/23/33/19), army
* Mage Staff, Necromancer's Helmet, Hero Armor, Boots of Speed, Necklace of Victory, Tome of Light, Sandro's Cloak, Clover
* Chaos (fire, air, mana burst), Darkness (mind control, weakness, and mark of darkness), Light (blessing, protection, twilight), Logistics (0 use), Education (Baldric)
Useful spells: general (divine strength, stone skin, dispel, dodge, concentration), antimagic, vengeance, berserk, vampirism.
The hero doesn't have Subjugation, which would have helped. I didn't win, but the battle was good.
I'll add another interesting battle. It would have been a guaranteed loss against the computer, but as it was, the mage managed to handle 400 out of 600 enemy mages.