Orcs have no magic. Warcries.

Does anyone know how an Orc's stats are increased? Attack is clear, it seems to have a 50% chance of increasing. Magic is the worst. But what about Knowledge and Defense? I couldn't figure out the order.

And one more thing. The skill tree says that a hero's skill reduces the enemy hero's magic by 1/2 of their own magic. Has anyone checked if this is really true? Because with the Orc's meager magic, the skill becomes practically useless.