Wolf-Spoor points to a thread on the RPGnet forums suggesting "Tangent" versions of the World of Darkness, i.e, settings that share the familiar names and ideas but mix them all up into interesting new takes.
The post that caught my interest was a Tangent version of Mage, inspired by Zoroastrian Magi.
Zoroastrianism, the religion founded by Zarathustra, is most commonly associated with dualism, although this is a western misconception. The Greeks and Romans seem to have had their own misconceptions about The Magians (although they note explicitly that they do not engage in Sorcery).
Anyway, although it’s a religion still practiced today, it is also makes a suitably exotic basis for fantasy mysticism.