Necropolis discussions.

By the time vampirism appears, there are already more than 60 vampires, but even if vampires are affected by vampirism, they are not that difficult to defeat. No good player playing as Necropolis will leave vampires in a 1:1 fight against any other unit. Vampires are targeted first and with all available forces. Only if the game is quite long will vampires affected by vampirism perform well. But only in that case, because vampirism looks much better on other units. IMHO.