Thread:Zetsuen/@comment-26250681-20180707202421/@comment-34260483-20180707215142

Slavery doesn't need a necklace to start, since it is magic, it is similar to contract magic, the collars is to identify them as slaves, and there is also the slavery tool that would be the collar used to control monsters, these were put in arisa and lulu.

In summary:


 * Magic Slave and Geass = Magic
 * Slave collar = Artifact