Great Sister is a living demigoddess, and as such does not offer magic. She is not the head of a cult, although she is often involved with the activities of the Deezola cult. The Lunar Provincial Church answers to the Red Emperor, NOT the Great Sister.
Her greatest involvement is with the Sisters of New Consciousness, a Nysalorean school founded by her. Think of her as a leading Nysalorean teacher. She likely teaches stuff like the supreme calling of every human being is to aspire to self realization and only actions that kindle one’s seventh soul are worthy of the name of actions.
