Locke & Key: Breaking down what the keys are and what they do

Crown Key

The Crown of Shadows is introduced fairly late into the show, and the key itself is only mentioned in the penultimate episode of the show. The Crown Key must be paired with the Crown of Shadows for the crown to work—without the key, the crown is nothing but a piece of jewelry.

Echo Key

Arguably the key that started all the mess in Locke & Key, the Echo Key can bring back a person from the dead—but though the being is tangible in every way and form, they have limitations.

They are trapped within the confined space where they are summoned—in the comics, the well-house was the only place where the echo could be created, but this rule may not hold true for the live-action series.

The echo can only escape via the use of the Anywhere Key—which is why Dodge (Laysla De Oliveira) was so desperate for it.

Of course, the Echo Key doesn’t actually bring the real person back to life—only creates a realistic echo. The purpose of the key is more to satisfy the desire of a person who misses a loved one.

Also, it seems the Echo Key creates an echo of the person from the moment of their death—hence the key summoning Dodge in Lucas Carvaggio’s (Felix Mallard) body because that was the form in which Lucas died.