Natives of the Talhani Isles

While The Assembly rules over The Talhani Isles, they were by no means the first people to settle here. Even before The Atotakah laid claim to the region, the Isles of the Talhani Sea were long inhabited by people who still reside there to this day, though there presence has been largely dwarfed by the colonies of the Assembly.
Before the Atotakah, three major species inhabited the isles: Triton, Sea Elves, and Lizardfolk. Notably, all of these people are amphibious to some degree; something that allowed them to florish even during Atotakah's reign and now that of the Assembly's.
The natives of the Isles tend to be tribalistic in nature and live in more remote areas that are less accessible to the land-dwelling colonists; something that has allowed them all to live in relative harmony. All of them have some degree of communication with the Assembly kingdoms, with Triton tending to be the most social by far and Lizardfolk tending to be the most isolated, but only slightly more so than the elusive Sea Elves, whose fully aquatic societies put them the most out-of-reach of land-based civilizations.

Culture

Major language groups and dialects

Unlike the other Assembly nations who have adopted a common tongue, natives of the Talhani Isles still favor their original languages, with Triton speaking Aquan, Sea Elves with their own dialect of elvish, and lizardfolk speaking a derivative of draconic.

Art & Architecture

While each individual group (and even settlements within them) have a unique sense of art and style, most of them take advantage of the natural beauty of their surroundings. Sea Elves and Triton build their settlements within coral reefs and fashion jewelry out of readily abundant pearls, shells, and sea glass, while lizardfolk are masters of crafting with wood, fibers, and animal bone.

Common Customs, traditions and rituals

A common faith or spirituality shared across the native groups is that of the Invokers. Despite vastly different backgrounds, each group has similar ideas about gods having once resided physically in the Talhani Isles. It is there believe that these "Invokers" left clues and tools behind that will eventually lead those who find them to reach a new, elevated state of being.
There is also a shared, common thread involving the so-called "Deep Dwellers," eldritch beings that reside in the deepest reaches of the oceans that occasionally surface and sweep across the lands like unthinking hurricanes. To be clear, these are not gods to be worshiped, but natural disasters to be avoided.