Along with other Fae artifacts passed down from one Ash to another, the Koushang was kept inside an amethyst crystal in the Light Fae trophy room. Lauren gave Bo the map and key to where it was located.
Afterwards, Bo wore it when she confronted Aife and it stopped her from being able to chi-suck Bo.
The Dark King that tortured and raped Aife while she was his prisoner wore a Koushang to protect himself from her succubus powers.
- 1.13 Blood Lines