In the campaign for the Empire, when it becomes possible to buy a fire mage IMMEDIATELY buy it! This is the best hero of both companies. At first, he has an excellent fireball spell, but by swinging the magician up to level 25, it becomes possible to use the meteorite spell. So, buy and collect for this hero those items that increase mana and reduce its recovery time, and you can take out enemies long before they arrive at the distance of the battle.
In the company for Chaos, you should not download the skills “duel” and “command” – they will manifest themselves. And with the “fight” skills “protected”, “ax throw” and “unreal strength” you will pass the test of the gods the first time.