Wow. That is like almost exactly what happens in Conan the Barbarian (1982).
I'm not really considering roles right now, though I guess healing might be in slightly shorter supply. Really just piecing together a campaign setting using the Tier 4 classes as inspiration.
Religious Adept is a really good catch. Palanan's city-state temples could have domain adepts (giving them strange spells granted by their unnatural/manmade gods, the nature gods being a bit more passive I would assume) while the barbarian/tribal witches/adepts still have familiars (which flavorwise feels on point). I like the idea of more cloistered clerics in robes who are political schemers than full-plated holy warriors. I also like when they get 8+ level they get lightning bolt instead of fireball, which gives them a sort of Emporer Palpatine–style menace.
I too am not sure if Spellthieves can take Shadowcaster's powers. If I remember correctly they act like spells for a certain time then become spell-like abilities, and the Spellthief does say something about stealing Warlock spell-like abilities. So maybe. With the adepts really taking on the religious caster roles (and becoming more prevalent in society), I guess I could do away with the sorcerer/wizard npcs altogether. Instead you have spellthieves sort of filling in for them: they would probably be the ones really throwing around enchantments and divination and transmutation, meanwhile stealing the powers of the other casters which leaves them as sort of predatory outsiders to the rest of the magic-users in the setting. They hint at the possibility of wizards/sorcerers in the past, a long dead civilization whose ruins litter the world and hide the magic items they crafted so long ago. A spellthief would just be the last and weakest in the long decaying line of those older, more powerful traditions.
Warlocks indeed could fit into the setting as well as probably several other classes but for now I'm going to stick with the core twelve I started with and see if during brainstorming anything would come up which would preclude other classes. Like right now, I know any of the classes in Tier 1 and 2 are out because this is already a sort of lower magic or at least a stranger-magic setting. Though eventually things from 3 and 5 could possibly appear.
I am waffling back and forth on paladins because while I do like the idea of them being enforcers for the city-state temples, there's just something about the pure Lawful Good shining knight which has always appealed to me. Perhaps, they are born to fulfill a certain purpose which they discover over the course of their adventuring careers.
Anyway, I've been thinking about the origins of the setting. I'm drawn to two descriptions from Incarnum and Shadow Magic:
- "Before creation, darkness was all, and it waits even now beyond the edges of all worlds."
- "Incarnum is an amorphous magical substance made up of the soul energies of all sentient creatures—living, dead, and, it is theorized, those even not yet born."
So it goes, the potential soul energies of life was swimming around in darkness and eventually congealed into the world. Something like that...