Preindustrial enslaved mages. Three groups separated by a forked river. One is a mageocracy, one enslaves mages (pretty horribly), one doesn’t do either but is very xenophobic. Outsiders born there could potentially be mages. Glad to be a setting or send visitors. Could use intervention.

https://notebookundermydesk.wordpress.com/glowfic-authors-page/setting-river-sparks/