NHF – new heroes for Heroes V 3.1.

I think this idea is quite interesting, even if only for the final stage.

In my opinion, simply reducing stats isn't interesting – to achieve a certain universality (i.e., without depending on whether the enemy has an artifact or not), you could reduce their stats (or increase your own in opposition to the enemy's stats). A special ability tied to the artifacts equipped on the enemy would be interesting if it didn't just reduce basic stats, but rather effects like elemental defense/enhancement or a bonus to speed, and so on.