|"What manner of faerie are you?"
The title of this article is conjectural. Although it is based on canonical information, the actual name is unknown and may be changed when new information is released.
This unknown object is one of the Dread Trove.
It is known that the object is made entirely or partially of ancient bone.
The Cauldron made many objects of power long time ago. Most were lost to history and war.
When Nesta Archeron went into the Prison with Cassian, they were attacked by Lanthys who shows Nesta a vision trying to seduce her to his side. In this vision, he shows her how they could rule together with the help of the Dread Trove, the Mask, Harp, and Crown. However, there was also a fourth object but since it was veiled in shadow she couldn't make out more than a gleam of age-worn bone.