Hi, first to preface I am relatively new at playing, have collected for a while but haven't had much opportunity to play. Now the questions, I understand that you compare the attackers att w/ the defenders def, let's say for arguement that the attacker is a 6/4 and the defender is a 5/5 after the resolution of the chain and both are 3 drops. Assuming also that no one is reinforced, the defender would take 1 breakthrough + 3 for It's cost for a total of 4 endurance loss. Now the counterattack, is there breakthrough damage? does the attacker take 3 or 4 endurance loss. I was playing that breakthrough happens to both untill recently and another player stated that the attacker doesn't take breakthrough. Appreciate any insight. Thanks.

Defenders do not cause breakthrough.

Easy enough! :)