(like seriously, what is Corvermell's wealth or strategic resources? Do you even have oil fields? Gold? Coal? o-o )
FUNNY STORY!
when I was drawing housekeepers with a metric ton of gold jewelry, I realized the disconnect. of course, all that gold was traditional jewelry, that all the housekeepers are supposed to wear along with the trademark red robes, and have been doing so since medieval times, but if they're traditional, then where in heck did these ancient islanders get so much gold from without trading it with another nation?
so then I figured, well, Corvermell has a ton of gold then. and it's like the aztec and inca, there was so much dang gold they didn't think much of it at all, and just kinda tossed it on everything cause it was pretty and cheap.
but then I asked, "so why the hell didn't the price of Corvermell gold hike up by a mile when they discovered other nations, making it impossible for vermellans to buy it? why was there never any colonization effort to take all that dang gold?" and then I started thinking up a really complicated solution to this economic problem of Corvermell gold inflation.
to make a long story short, when the outside world discovered Corvermell, there was a gold rush that lasted about 4 weeks. the housekeepers of that time, concerned at what they perceived to be an obvious invasion, passed a law forbidding the sale of Corvermell gold to foreigners, and forbade foreigners from mining Corvermell islands for gold. for many years after that, enterprising businessmen were stopped by force of militia until everybody got the point.
even today, you can't buy gold in Corvermell unless you're a born citizen, and born citizens leaving the country can only carry so much gold jewelry as they can wear onto the plane. this has created a bit of an artificially high price for smuggled vermellan jewelry, which on the black market, is more expensive than those fancy watches.
so to answer your question, we have gold. we don't let anyone else have our gold. don't invade us for gold.