Madame Velix is a Geisterdame who seems to be the person in charge at an opera house in Paris. She is evidently undercover, as she wears a blue suit rather than traditional Geisterdamen clothing, although the garment incorporates some of their restrictive "criss-cross" motif into its design. When Velix is first introduced, there is a pair of goggles equipped with fake pupils lying on her desk, perhaps enabling her to pass as an albino human.
The opera house is preparing to stage a production about and/or starring the Queen of the Dawn, and Velix's collar-insignia openly identifies her as working for Her Highness.
She is capable of speaking English (or more likely French) and does so with her human-appearing minion Sophie, who brings her the unwelcome news of of the arrival in Paris of Agatha and her wasp eater.
Unwelcome because Velix is also involved with, if not leading, a conspiracy to smuggle large amounts of miniaturized slaver-wasp hive engines into Paris; it is eventually revealed that a sizeable portion of the city's population has already been infected, and that there is whole cadre of Geisters in the city, all dressed similarly to Velix.
One of these, possibly Velix, is working with The King of the Silver Lands, and personally assists in his attempted of the Immortal Library of the Grand Architect. (Whoever she is, she also shares more of his general hamminess than has been seen in Geisters to date.) In the process of this, she is by Larana Chroma and the miniature hive engine which she has been lugging around is evidently noticed by Dimo, but plotwise nothing seems to come of this latter reaction.
A later Colette Voltaire as the new Mistress of the city and the subsequent thwarting of the take-over plot. Again, it's not 100% certain one of this group is or isn't Velix. Their attempt at destroying the physical evidence of the plot (or at least their take-out order history) is stopped by the arrival of Agatha and her retinue; Agatha's successful use of the Command Voice on Sophie unsurprisingly shows that the latter woman is a revenant. The Geisters, however, all fight to the death, and one of them deliberately runs Sophie through with her sword before being dispatched herself.shows Sophie and three Geisterdamen bemoaning the rise of