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

This is a very complex question, and it's impossible to answer it definitively. If we compare the factions in terms of the overall strength of their creatures, then the Dark Elves are the strongest. But they are the worst for storming cities. And Demons, with their ability to open portals, are simply excellent for storming cities! You can block almost all ranged units and then bring up the main forces to them (while they are fighting the summoned creatures). This ensures the fewest losses compared to other factions. Since storming cities is the main key to victory over the enemy, I voted for the Demons!