So just for a quick "historical" context. This is a continent where numerous races other than humans exist as does somewhat weak magic. In the medieval era the humans attempted to genocide/enslave all the other races in the calamity war. Ultimately they were defeated by an alliance of non-human nations lead by a hero (non-human) who most believe is a goddess of nature and war. There are no more human nations now, as all of them either got conquered or collapsed due to famine (wrath of nature). Humans still live though their numbers were severely diminished.
Her children, using her godlike status, army and approval of their allies, create a kingdom of their own, Piena. Now they are obsessed with the idea that their kingdom becomes incorruptible and its ethics do not change, because of events in the war. Even through the ages. So they decide that the most rational way to proceed is to brainwash (includes a combination of magic, drugs over long periods of time) their ideals into the next generations.
Unfortunately Piena can't brainwash everyone. Piena can't brainwash its allies, because diplomacy. Piena can't brainwash its entire population, because money. Piena can brainwash it's nobility and royalty though. Piena can also brainwash the people doing the brainwashing. Also we are assuming that everyone knows about the brainwashing and the nobility of Piena is fine with it initially.
Some general information : Piena is situated at a crossroads of most of the major river-ways in the region and as such is hard to avoid inland. Its territory contains those of an old human nation as such it has about 30% of its population being human. It has very fertile soil (from rivers) and thus a large population (especially for after the war) but not other riches except its strategic location and army. Genocide should be avoided but slavery is completely fine. At the end of the war all nations which didn't collapse were in the winning alliance so at least initially Piena is surrounded by friendlies and doesn't have to worry about an immediate military threat other than bandits/small warlords from the collapsed remains of other kingdoms. The hero is also worshipped widely outside Piena's borders though there are different churches, some of which don't consider her children divine. Pilgrimages to her mausoleum in the capital city are widespread in all cults. In the stories told by priests she is basically a mary sue.
Now because asking "how would this work" is a bit to general here are some specific questions :
- How would the founders organise Pienan society to ensure long-term stability ?
- How would other nations (which are initially all allies) react and how should Piena respond to them ?
- What to do if brainwashing fails or is only partially successful on a member of the royalty (who are believed to be descendents of a goddess including by some cults abroad) ?
- How would the brainwashed leadership, say 600 years later, assuming they survived this long, react to things like industrial/magical revolution, which the founders couldn't anticipate (note that the founders MAY not be averse to "technology" but couldn't anticipate such rapid changes) ?
- Now say you are a foreign nation, how would you take advantage of this situation ?