Mól clans as pre-imperial nations
The great clans were nations in their own right before there was a Mól empire, and every curse-keep is one clan's heartbeat
Before there was a Mól empire there were the great clans, and they were not factions inside anything. They were separate nations with separate laws, and they became one state by argument rather than by conquest: that together is stronger. From outside the Empire looked like a single enormous thing. It was built out of a treaty.
Each of the seven keeps is the heartbeat of a single clan, holding that clan’s relic, and the seven of them together are the seven old nations laid out on a map (S4E49, S6E69). Their architecture and their function differ so sharply from one keep to the next that they read as separate countries, which is what they were.
Hinta set this out for the party in S6E69, under a radiance-crystal tree, where she and Koa had fallen to talking Mól history and she set her clan’s traditional lore beside his firsthand knowledge of the keeps. She grew up a few miles from Wraithblade Keep and never knew it was there. Which clan held which keep is being worked out one keep at a time, and the list is not finished.