Description
The symbol of this charm matches a line of powerful women in Telara's history. Scholars refer to them as 'the Dominata', and like Nyx, they worked by selecting a man to be the puppet behind whom they could pull the strings. Each of them was depicted with the charm somewhere on their person. Nyx must have been the first of them and passed the charm down.
This particular charm was beneath the sea, so it can't be the same one. They say that Estrael and Nyx had a very close bond, so I wonder if this was a matching set. Maybe the two charms can be used to find one another.
If there's anywhere the Dominata might weave her magic, I think the most likely place for her to find success is Fortune's Shore. Start looking there.
Upon completion
The heir of Nyx? I certainly don't know what you're on about.