Well given that I am guessing at a 200 person population (1 packed boat), possibly a second boat if I let the second boat find them. 25 percent Deryni (50 Deryni and 150 of their supporters and hirelings. They are outnumbered and surrounded by humans. Given the powers at their disposal the question is qhat do they have to do in order to survive, and can they maintain a sense of identity while doing that.
So I think there may well be a office of special projects that works to control things in their favour. I like the Operative's line from Serenity. He is arguing with Mal about building a perfect world and says there is no place for himself in that world, he is a monster. So do some people do the dirty work to let others live in happiness?
So I have visions of a Deryni Cabal of puppetmasters working to hide their efforts from the Natives and the rest of the Camberlanders.
Many of the Camberlanders are happy to live and trade and work to build good relationships with everyone around them. But inr eading about the culture of the area the raiding aspect and vendetta wars would result in a war of attrition that Camberland could only lose. SO I have to come up with a way to prevent that. Other ideas for stories I have include being the helpful neighbour and the trader with really good prices. Again using the Portals and healing aspects of their magical heritage to offer them a competitive edge. The question I put to myself is how does a village surrounded by other people without a technological edge survive and prosper? In our own history the European settlers had guns, and iron weapons. Slow as the guns were they were a big advantage. Camberlanders do not have that. They have iron weapons, but no guns. Their bows may be better, but they are still outnumbered thousands to one.
Their only advantages are their technology in terms of iron weapons, and farming techniques. I threw in the growth of animal pens totake advantage of the maggot filled gren, because I am a geek and that is what I am interested in.
The other advantage is their Deryni magic. Mind coltrol to control village leaders to not attack Camberland is an overt use of power.
Healing offers a faster return to duty for wounded soldiers in a miltary operation. Rapport and mind speech and mental imprinting of knowledge offers faster training and a way to preserve knowledge. Mind speech at a distance offers a communication network that medieval military and economic minds would have loved. Last but not least is the Portals. I freely admit to liking the teleportation trope. It is one of my favourite fantasy and sci-fi elements. It offers low cost, rapid transit of goods and information. If you start to build a network and can shuttle goods, people and information around you can build a community faster than people trying to carve out a life without support.
I'll write a story later about settling an island with a Portal. It might go something like this:
Group arrives by boat on island and picks a spot for initial village. The group has 6 people, all trained Deryni and human followers to provide power for the Portal construction.
A portal is made. The Deryni then teleport back to main island and returns with passengers.
More trips are made each day to bring in tools and supplies. A boat could be used if the island is close enough, but a Portal would be much faster.
The village is built and the resources of the island are developed.
If there is a problem the Deryni can call for help telepathically if the island is close enough. (within several days ride, distance is open to interpretation on that, from Deryni Magic page 48). Or a Deryni can transfer via portal to get help from off island.
In this way Camberland can divert resources in a planned, efficient manner to a given problem. Portals still offer limitations in rate of transfer, but as I showed in the one story, pairing human and Deryni allows for rapid deployment of troops, far faster than trying to get boats together and sail to an island. Besides, in a new land suck as Camberland, they do not even have enough boats to transport troops in that manner, aside from the one sailing ship. So portals would be the main method of island travel. (In my opinion at least).
This would also present themselves as extremely powerful to the Natives. Every culture has superstitions, but here are people who actually do appear out of thin air, no superstition, they actually travel instantly from island to island. They can also conjure fire from their hands and call light into being with a simple gesture. Hence the name "Lords of Air and Fire."
It's geeky and wacky amd not at all set in the world that KK has described so vividly in her books, but I like taking ideas and planting them in an entirely new situation and seeing what would happen.