Swarmcallers

An elite group of rangers who live deep in the ocean on a variety of air and sea vessels. Over the course of the last 50 years the Swarmcallers have rediscovered and adapted a large chunk of the old-world nanotechnology. Roaming a large chunk of the Pacific and Arctic oceans their flotillas and fleets evoke images of flocks or whales migrating.
Waves of ships, with nimble skiffs zipping in and around the fleet, ropes and tubes reaching into the sky connecting to a variety of balloons, planes and other flying/floating in the skies above. Swarmcallers use their magical nanotech to float through the sky, propelled by their bots. Others use them as an oxygen-providing suit, allowing them to spend long amounts of time underwater. Their swarms provide massive protection and adaptation to different terrains and biomes.
Within the clans its generally assumed that while there have been generations of master swarmcallers, they are just barely scratching past the surface of what is possible with their swarms. Most swarmcallers (even the most adept) can only control a swarm about the size of their body, but theoretically the sages and elders of the Swarmcaller clans don't see a theoretical limit to what swarmcallers can do, their limit seems to be a mental or maybe magical one.
Outside of the Swarmcaller community it's generally assumed that there is only one large group of callers that make up the entire population. While technically true the Swarmcaller nation is made up of a variety of clans, something that the outside world has little interest or understanding in. Lots of racism from the surrounding world, reducing Swarmcaller nations to pirates, scroungers and murderers. Like all nations this is true, and deeply reductive and racist.
While the Swarmcallers themselves come from all across the globe in pilgrimage to learn from the elite rangers there, their nomadic settlements require a large variety of skills and talents, children of the great Swarmcallers generally stay with their clans, family (magical or not) are always welcome and needed in the fleet.