I was playing a fat goblin and as the overlord I played critical blow.
This attack gains a serge +3 damage
What a great basic card!!!
My question is can you use this card even if your attack failed to roll a serge to add 3 additional points of damage ? Or does the +3 damage for the serge replace the existing serge damage on the monster card? ie you need to roll a serge to use this card?