NHF – new heroes for Heroes V 3.1.

2) The reduction applies for one battle.

It can be for 1 battle or 10. There's the concept of the final battle, and there's the concept of a stat reduction. In the final battle, your maximum stat is halved against this hero.

3) At level 20, the maximum stat usually reaches 12 without Education and artifacts.

However, there's also Education and artifacts, thanks to which the stat can reach values of 15-20.

4) Well, a mage will have maximum Knowledge, but what's the point? There's already a huge amount of mana.

I'm talking about Knowledge; your special ability doesn't work against it. Is that a feature?

5) The maximum stat can be adjusted with artifacts so that another stat is reduced, effectively bypassing the special ability.

So, you have a primary stat, for example, Magic at 16. Should you adjust Attack to 16 to get a -8 penalty to Attack? Should you try to play with balanced stats without a primary stat, just to counter the special ability? Should you max out Knowledge? Isn't that a bit much for one special ability? And even if it's a "counter," with balanced stats, you'll have around 10, a -5 penalty, which is quite noticeable. And even if the "counter" is played out, the bonus remains decent.

6) I already suggested stealing the minimum stat because it's better, so what's the point?

Where? The last sentence seemed to be about halving.

Added 2 minutes later

Or it reduces the enemy's minimum stat to 1, taking the difference for itself.

Oh, I missed that. But that's even worse. If the enemy has a minimum defense of 6, it becomes -5 defense, plus +5 for the hero? Just leave it at a minimum of 1. Without any bonuses for the hero.