I'll disappoint you, but they're noobs. Sworn Enemy doubles the damage.
Added 4 minutes later
Elves are my favorite Castle. I really liked the combination of Sworn Enemy and Dark Magic. I tried it on the "Frozen Land" map. There, on the neutral territory, there are neutral peasant units with over 100,000 units. I defeated them with a squad of 150 upgraded archers, 70 druids, and 30 ents. The peasants were Sworn Enemies. Enchanted Arrow - Berserk. Using the Arrow Rain spell, you apply this enchantment to all units and just wait for them to kill each other. I don't think you can do this with any other Castle. One drawback is that you can only change the enemy in the Castle.