Sculpted by: Arlen Pelletier
Release: 2016
Edition: Limited, only available during first pre-order month for Bode bust
Used material(s): Plated in an antique brass finish
One of: 600

Signed: No

Reissued in Ghost Door box since 2021

First appearance: Did not appeared in comics (yet)
 A mystery
 An even greater mystery

More information:
(possible spoilers)

Will the Enigma Key appear in future Locke & Key stories? Good question. Only Joe and Gabe know the answer to that.

Will it appear as a future release from the studios? It will not.
The only way to grab the Enigma Key is during the first month pre-order for the Bode mini-bust. After that, this key is officially sold out, not to be released in any way, shape or form again.

Source: Skelton Crew Studios order page (offline)