There are various ways to help your units survive in Artifact. You can heal them, give them armor, damage immunity or even swap them with another friendly unit to make sure incoming damage isn’t fatal. And then there’s the ultimate last resort, Death Shield. Death Shield doesn’t block incoming damage entirely; it just ensures a unit survives otherwise lethal damage with 1 point of health. Upon negating the unit’s death, Death Shield is removed and the unit takes damage as normal.
So far only one card has this effect. Relentless Zombie — selfish ghoul that it is — applies the effect on itself. Quite necessary, as the creep doesn’t have too many bragging rights with its 2/0/2 stats.
Giving a unit a Death Shield is an incredibly powerful move to make. In most cases, it ensures the protected unit will live another round, dishing out damage or saving your tower’s health. If we take Relentless Zombie as an example: it is simply a punching bag preventing damage from going through for two whole rounds. But it’s not hard to imagine an offensive at all. If your unit with high attack is close to dying, but another turn of its damage will finish the opponent’s tower: pop a Death Shield on it (should a card that applies Death Shield be in the game, of course).
There are a couple of counters to a Death Shield. First is chipping away the shield with another source of damage. Grazing Shot or Keenfolk Musket, for example, have relatively cheap ways of dealing the damage. Secondly, you can purge the effect from a unit using cards like Apothic Shield. The hardest counter, however, is playing a card with condemn like Slay or Coup de Grace. Death Shield prevents incoming damage, but since condemn technically doesn’t damage units — it just crushes their hearts instantly — Death Shields won’t have any effect.