We made some awesome faction and races in the past.
The idea now is to make a culture based on real world of humans.
The particular thing is that they live on an arcipelago of floating isles.
The islands are made of mangrovies that take nutrients from plancton and microorganism in the roots releases gases that make this living island bayonant. Islands are in the ocean.
So we start by answering questions:
What do they eat?
How do they procure said food?
How much floating land per person is needed.
A modern version of those floating island would look like picrelated.