As I believe I have discussed elsewhere, the starsisters are powerful demons. As such they do not exist in what we would regard as corporeal form. They need an anchor to remain long in the world of Khumkato–and that anchor is usually one of the starchildren.

What is a starchild?  Usually they are raised from birth to serve as host to one of the sisters. Most of the starsisters effectively operate breeding programs in which they maintain hundreds of slaves. These slaves are paired off in the hopes of producing offspring that will exhibit certain characteristics. For example, Anhilisha values beauty above all else, while Anhilarya puts much stock in physical strength. When a girl is chosen, she is placed in a very specialize grooming program. In particular, they are fed a very specific diet of unique herbs that is supposed to slow down the damage inflicted upon their bodies while they are inhabited by the sisters. It is apparently an unpleasant process to leave one host for another, and so the sisters would prefer to keep a host as alive as possible, for as long as possible.

While this is the normal method, the sisters sometimes will choose girls from the general population, if it strikes their fancy. This has led to various noble families–and even some peasant ones–to bring their daughters forward as sacrifice in the hopes they might be chosen. If they are, the family often benefits by the association. Of course the child suffers a hellish existence while her mind is slowly extinguished and her body is eaten up painfully from the inside out. Therefore, while it would seem to grant the family some “advantage”, in fact they murder a very large piece of their soul in order to gain it. I have met some of these people, and I can say that the spiritual scars run deep and are still evident even generations afterward. But then again, anyone willing to doom their own child to such a fate is already so far beyond moral reason that I doubt they even realize what they’ve done.

Hmph.  And bear in mind this is from the perspective of a professional assassin. May the gods have mercy on those girls.