- Comparison of creatures from Heroes 5 with creatures in Heroes 3.

I actually liked that. It just depends on what vampires drink from their victims – if it's blood, then they shouldn't be able to regenerate from undead. But if it's life force... then it's very possible! After all, something must be making that skeleton move :) If it's magic, then why shouldn't they be able to drink that magic?
In short, since we don't know much about necromancy (probably:)), it's hard to judge.