In your opinion, which faction is the strongest in Heroes 5? Let's discuss the advantages and disadvantages of each faction.

You say that Dungeon is stronger? Then why did 10 of my Paladins, led by Axel, easily defeat 13 of my friend's Black Dragons (without any luck)?

Because you're either mistaken or playing version 1.1/1.0, where the cavalry charge and Axel's specialization haven't been nerfed yet. Only in completely absurd assumptions: 1. You have expert attack, and your opponent's defense is not upgraded. 2. Due to damage variance, 20-30 Paladins dealt exactly 30 damage. 3. Might and Magic Week (!!!) (the biggest bonus of all weeks). 4. Presence of Retribution and Morale 5. 5. Level 25 hero and 8 movement points for the Paladins. 6. Your hero's attack is 46 points higher than the enemy's defense (!!!!!). If all of this happens simultaneously, you could defeat 13 Black Dragons. Because then: damage = 1.15 * 10 * 30 * 1.5 * 1.25 * (1 + 0.4 * 1.5) * 3 (stacks) = 3105 - approximately 13 Black Dragons. Theoretically possible, but in practice...