The Maremastras Stories: Tales of Sea People Landers and Assassins

These stories are about people living on offshore rigs in the seas of Earth (a minor planet in a universe not far from our own). Most lander nations claim that the rigs and structures off their coasts fall within their own sovereignty. Almost universally the nearby lander governments have been appalled by the successes of the rig people. Time after time their forces have sought to assert that sovereignty. Given the respective population sizes, you might expect the end of the rig people. But there was a finger on the scale. The finger belonged to the Assassins.