The islanders are people from the many small islands scattered around the world. Their remoteness and lack of important natural resources meant they stayed out of the radar of bigger nations and empires until relatively recently. Even though each island has developed its own thousands of years worth of unique cultures, the larger nations tend to group them all as one "islander" archetype, not bothering to differentiate one island to the next (even when said islands are in opposite corners of the world). The most obvious physical characteristic of the islanders is that they have unique skin colours: red, orange, yellow, blue, purple and pink. There does not seem to be a logic behind the spread of the colours (only that one island tends to be populated by people of a single skin colour), or a reason why they would develop such colours (the scientific community has long established that skin tones ranging from black to white have to do with exposure to sunlight, while green hues are linked to camouflage in forest environment). Nowadays islanders are perceived as uncultured, technologically behind the rest of the world. They are, however, praised for their "old ways of life" and are considered highly desirable partners for those who want children of "funny" skin colours.
Shared customary codes and values
The only thing islanders seem to share across the board is their sense that life was better before they became "integrated" in the world. Now, they have to put up with people who seem unable to understand that an island in the frozen north is obviously not going to be the same as an island in a tropical climate.
For some islanders, "anyone who isn't a mainlander" is the minimum standard for a relationship. On the other hand, plenty of islanders of all islands have moved into the main continents and actively seek partners from their new homes. Those tend to not care whether such partners are the "island chasers", and will go along with anything in order to have a partner from the mainlands.