The strongest castle in Heroes of Might and Magic IV.

LeSHiJ-MaX, I'm not insisting that I'll convince you, but... As a fan of Nature, you should understand that against Death, it is one of the worthy opponents.
Water elementals will deal with Vampires (you can, of course, use others, but I think it's the most worthy). Moreover, it has a cold attack, even when it's blocked, let's say, by Vampires, but they won't get a charge from it to restore their lives.
Nature has a powerful WEAPON - the Necromancy Ward. It won't allow Death to raise the dead.
This is the most important thing. Therefore, Nature, in skilled hands, can succeed.