Ash Lock

Standard equipment used by the Executors of the Holy Church.
Unlike the Black Keys that Executors are also known for, which take a considerable amount of training to use effectively, the Ash Lock is a powerful Conceptual Weapon that can demonstrate great ability with a minimum of training. Normally they are disguised as gloves or boots, but by removing their tag, they revert to their original form.
Used by a large number of Executors, they come in a variety of forms. While Ilumia elected for a hand-to-hand fighting type, versions using things like small blades or crossbows also exist.

Lord El-Melloi II Case Files material: Lord El-Melloi II Case Files Glossary