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

Burns units that are about to cast spells (like liches) for 10 damage per hero level.
But initially, they are good on huge maps where you can accumulate units and build a castle. However, the units have a poor cost-effectiveness ratio.

Yes, why would you waste a hero's turn to burn liches? Or is this a constant effect on all mages? If so, liches are also quite effective with their blades, and their spells aren't that great. It's better to spend mana on Pit Lords' "Mana Burst" or Druids.