DoorkeeperHow it works & interactions with other cards

A Wall That Mills

Doorkeeper is a 0/4 creature with the defender keyword, meaning it cannot attack. Its true power lies in its activated ability: by paying {2}{U} and tapping it, you force a target player to mill cards equal to the number of creatures with defender you currently control.

Calculating the Depth

When you activate the ability, you choose a target player. The value of X—the number of cards milled—is not determined when you activate the ability, but rather at the moment the ability resolves. If you lose or gain creatures with defender while the ability is on the stack, the final count will change accordingly. Note that Doorkeeper counts itself since it has defender.

Strategic Implementation

Common mistakes often involve forgetting that the count includes Doorkeeper itself, or assuming the number is locked in when the mana is spent. To maximize the effect, you should aim to resolve the ability while your board is at its peak number of defenders. If Doorkeeper leaves the battlefield before the ability resolves, it will still use the number of defenders you control at the time of resolution to determine X.

Interaction examples

Single Sentry Mill

With only Doorkeeper on your battlefield, you activate its ability. When it resolves, it checks how many creatures with defender you control. Since Doorkeeper has defender, X equals 1, and the target player mills one card.

Defensive Synergy

Ornithopter of Paradise

You control both Doorkeeper and Ornithopter of Paradise. Because Ornithopter of Paradise does not have the defender keyword, it does not contribute to the value of X. When Doorkeeper's ability resolves, the target player mills only 1 card.

Scaling the Wall

Foundry Inspector

If you have two copies of Doorkeeper on the field and one Foundry Inspector, only the two Doorkeepers possess the defender keyword. Activating one Doorkeeper will result in X being 2, forcing the target player to mill two cards upon resolution.