NAF – New artifacts with unique properties.

So, we can't influence the enemy's speed? (what about the "Embrace of Death" set - reducing speed by one from two artifacts)

But it doesn't work through scripts...
Although, on the other hand, if such an effect exists in the game, it's possible that the effect could be "copied" for another set by tinkering with the executable file. But it's unlikely that the mod authors will deal with this, as it's not that simple.