The main question: what to do with Dark Magic? There are 3 possible answers, depending on which skill you manage to acquire.
A) Dark Magic with two seals. Then it turns out that we have two identical magic skills with the Necromancer. In this case, the main thing is to take Druids with Channel Magic to keep up and maintain order. Plus, there are Unicorns with resistance and magic resistance in the Luck branch – that's more than enough. Moreover, we will be able to cast mass slow, while the Necromancer won't, because we have both seals and horses, and magic resistance in Luck. This option is generally great if you know for sure that the Necromancer has invested in Dark Magic.

B) Sorcery and Counterspell. Then Empathy will have a 200% effect. If you are sure that the Necromancer hasn't invested in Horror Scream, then Empathy is, of course, unnecessary. But even with Inspiration, the Elf will feel quite comfortable. If you manage to get Counterspell, then just take artifacts to increase your knowledge as much as possible. And catch the Necromancer off guard. If you block the Necromancer's magic, the troops will be left to fight one-on-one, and the Elves' advantage will increase.

Conclusion: Dirael is unbeatable against Necromancers! He's overpowered! And people are trying to squeeze the last bit of juice out of the weak Warlock, who is having a terrible time at the start. :))