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It depends on the type of magic. Berserkers are useless without magic, but with it, they become overpowered. However, pure barbarians, even with a stack of 900 berserkers, can't do anything. They could only win by using birds with harpies and relying on initiative and morale to eliminate the heroes before their turn. All other options are weak.
That's true, it makes sense. Because morale is important, and the experience gained by vampires is reduced due to necromancy. But what to do about it is a mystery.

Барон "Vampires"
Отдай свои прошлые сны,
В сомненьях себя обрети,
В бешеном танце душа кружится!
Не думай, что будет потом,
Здесь и сейчас мы живем,
Стань хоть на миг сам собой, слышишь!