Auto-translated
The best hero is one who is skillfully leveled up!
Regardless of whether they are a mage or a warrior... but actually, when choosing a hero, you should be guided by their specialization and the skills they lean toward. For example, two heroes with the same specialization from the Necromancer castle, Vidomina and Isre; I always take the necromancer Vidomina because she is usually given Earth and Air magic, which is very important to me, and intelligence drops more often for a necromancer than for a death knight. In the early stages of the game, attack and defense are certainly lacking, as is the case with all mages... but the main thing is to clear at least a couple of Dragon Utopia and everything will be ok :) So in the Necromancer castle, my priority leans toward mages.
But in the Elf castle, it's exactly the opposite; I always choose a ranger as the main hero, Kirya or Ivor (well, if I'm lucky, Gelu is best of all :)) in my opinion, rangers are always given more suitable skills for this race + they usually develop more harmoniously than mages from this castle.