As used in these stories
The Witches Head Tradition was the Wiccan tradition in which Alexandra trained and achieved her third degree. As with any who had achieved the same degree, she was considered a high priest/ess while still on the surface.
She connected with a few other members of the surface tradition who mainly resided in North American Habitat Central and one other person in NAHE. At the time of the catastrophe, the Witches Head tradition had initiates in all three North American Habitats. Eventually, she was able to restore the tradition in her habitat, and some of those who became members of the tradition also became members of her extended family.
Besides the usual Wiccan practices, the Witches Head Tradition taught self-reflection and knowing oneself as paramount principles.
Witches Head followed a five-fold ranking system beginning with dedication, where students dedicated themselves to a pagan path, followed by Neophyte, where they prepared themselves for the rigors of initiation and then the three common ranks of initiates—first, second and third.