Technically you can counter it with holy flash/ holy light. you heal the opponent for ten hp. which in this case would damage it. it is effective against ai cause they tend to have a bad habit of using Shard of sacrifice multiple times per turn, leaving them with a small amount of hp.
its kindof amusing that a light card here is the anti death shard.
also you can stall with sundial. to prevent healing during your attack phase.
If anything it might be good to reduce the turns this card is active to 1 like sundial because the way the card works, healing yourself for all the opponents attack, that usually means that unless they have a bunch of creatures in reserve, they are going to heal you for two turns, then take another two turns to take all that healing off, resulting in a stall of 4 turns, which is way more powerfull that something like dimensional shield which stalls for 3 and doesnt prevent all kinds of damage. Make the card last for 1 turn and you get an equivalent 2 turn stall, which is worse than dimensional shield but it protects you from all damage sources, which still makes it a damn good card.