We scare the Berserkers, and they run to the enemy and attack him.

Hmm? And what is the probability that they will run to the enemy and not to us?:D And will there even be an opportunity for the hero to move if, for example, you place a Berserker on the nearest unit?
And regarding the fact that Ragers are good for Necropolis – that is quite doubtful. There is only one possibility here – if you immediately gather a bunch of Vampires and learn the Plague spell. And even then, it's uncertain. And it is very difficult to capture a normal castle with Necromancers in the early stages. You can only do it with Kaspar, if you train a catapult. There are much more promising races in this regard. For example, the Academy. Or the Dark Elves. At worst, the Dungeon.

Added 3 minutes later

We scare the subordinates and wait for the spell to end.

And then they cast it again:smile52: