I may just be missing something, but I cant figure out why there's a battle matrix on the actual character/hero cards.
The rules state that the battle matrix on cards is to acquire them from the rings, but the character cards don't apply - they are not aquired. You obviously don't add your character matrix values to your cards in hand in order to defeat encounter cards, because it would be much to easy to acquire cards.
Are they perhaps a mechanism to attack other players in the game? The rules and videos have no mention of interactions between players.
I believe it's just to show the total value of the character's starting cards.