Advantages and disadvantages of Elven heroes. Discussion of their biographies and abilities.

But Dark Magic isn't effective against Wizards, especially since the hero doesn't appear very quickly. However, Summoning has an important skill called Misty Veil (reduces damage and initiative of enemy archers by 10%, and there are three of them, as you know). So, as I think, Summoning magic is the most suitable against Wizards! And if you choose Light, by the time you cast Divine Power or Stone Skin, half of your troops will already be gone.

Dark Magic might not be effective against a Necromancer, but what about against Wizards... I don't understand.
And regarding the 10% initiative, yes, it's better than nothing, but it's not worth it. There's a skill in defense that provides +20% resistance to ranged attacks, which is much more effective against a mage.
P.S. And I used Dark Magic as an example; you can choose another one... although letting enemy units through is often more effective than upgrading your own, because your army often loses to the opponent's.