Fantastic Caste System: Subverted.  While the Eldraeic concept of darëssef is often glossed as “caste” in translation, and while the nine groups of acquiescents (those who serve higher powers), aesthants (those who create beauty), executors (those who plan and implement), hearthmistresses (those who maintain; despite the way the name comes out in English translation, by no means all one sex), plutarchs (those who work with money and produce wealth), runér (those who wield the Imperial Mandate), sentinels (those who guard), technarchs (those who think and build) and serviles (unskilled laborers) may look quite caste-like, caste systems generally don’t support multiple simultaneous memberships, the ability to move to any caste and position simply by acquiring the necessary skillset, or the corporate and individual equality of all the “castes” and their members.  (Well, except the serviles, but then, if you could acquire any sort of useful skillset, then you wouldn’t be a servile, now would you?)  So much for stratification.

Not that there aren’t a variety of unofficial class systems if you want to go looking – the traditional wealth-style division into fringers, underemployed, professional, leisured and investor classes, at least three of which the average person will move through in their lifetime, the Names, Numbers and Novas above it all (or, looked at another way, the Exquisites and Excellences, Perfects and Paragons), the Failed at the bottom of the heap, and suchlike, but it’s not as if any of those were formalized the way a caste system is.  And they are much less restrictive than many systems – social mobility is, indeed, ideologically encouraged.