Undead Archers are sort of the utility unit of the Fallen Kingdom. They are really not stat efficient, but their ability is extremely useful to help cover a lot of the deck's weaknesses.
Where Undead Warriors are your main fighting commons, Undead Archers provide a lot of support.
- They allow Ret to use his ability and stay safe.
- Movement is valuable and they often don't need to be moved as they can just Soul Shift.
- They allow you to take the space in front of gates by killing the blocker and then Soul Shifting in.
- They allow you to get a third attack where your opponent may be set up in a formation so you don't have enough flanks open for attacks.
- They allow you to not lose board position where you want to sacrifice a unit with the deck's various sacrificial shenanigans.
- They can protect a wounded champion from being killed as they can Soul Shift in front of the champion to replace the unit that champion killed.
- They are Fallen Kingdom's main assassins, allowing you to attack through blocks or even do double-shots from a single flank. You can attack, sacrifice the unit (maybe Hellforged Weapon or Dragos, maybe attacking it yourself), Soul Shift in an Undead Archer and then attack again.
Its cost and stats may look like it is too weak but the amount of utility they bring is really massive. Undead Archers are definitely not an economically efficient common, but they are extremely efficient for tempo, pressure and assassination tactics.