NHF – new heroes for Heroes V 3.1.

In my opinion, this is a very niche special ability.

But I think it's interesting. It's like a "trickster" right out of the box.
It just needs to be modified: instead of resurrecting with a portion of the army, it should resurrect with a new army (depending on the level). With something useful for the trickster – ghosts, for example. And an unlimited number of times. That is, to get rid of it, you need to deprive it of cities; otherwise, there's no way. That's it, suddenly a good guy )
As an additional option: to resurrect the hero immediately in the garrison of the nearest city. Then any siege is two battles in a row with this hero (outside and inside). Maybe it's a bit too annoying, though.