Can a Shadow Army attack Beorn? He is such an odd character, because he acts like an army in many ways, can attack shadow armies and take damage. Can he be attacked back?
I believe he can be attacked just like any other army, though instead of applying damage you remove tokens from his card.
Though, honestly, we've played this game several times and in all instances, the game is either already won by time he is placed, or one player is so close to winning that he's not made a difference either way.
In my opinion, the eagles are the most powerful force for the good guys. You get them early enough that you can build them up to do damage and cannot be attacked or removed by the shadow player.