NHF – new heroes for Heroes V 3.1.

It will simply be an overpowered ability, I'm afraid, and too much for Necropolis. It's true. They already have high magic and ghosts, plus the largest armies in the game, to easily finish off weakened opponents.

The percentage will just be lower. What's so special about that? Don't forget about the experience loss...

It would be better to create a copy of the plague effect, slightly change its appearance, so that it becomes a special plague that kills even protected creatures.
Any effect can be applied using scripts, and a copy should be made.
Currently, the plague of Hafa should only kill creatures that are not protected from earth and magic. In reality, this is no longer the case (it is implemented in a very primitive way)
And, for example, if the opponent has the Silanna's Cloak, it will reduce the damage by 2 times.