Talanti

The Talanti are an ancient group of people completely isolated from the outside world due to their chosen home.

Location

The Talanti live in the Terralesque desert. They are the only humanoid species to do so, but this is the only land they know. They're quite used to the colossal creatures that live there. In fact, they live on the back of a tarrasque.
Using its massive rock-like back as a foundation, the Talanti have chosen to live right on top of a tarrasque. Over the many years that the two have been bound, the tarrasque has learned to trust the Talanti, and it even relies on them for food. They guide it to fresh nests of ravenous animals, and then they feast on the leftovers.
Their proximity to the terrasque also helps them avoid any of the other leviathans that could target them. As the Talanti see it, the back of that creature is the safest land in all of Distotia.

Customs

The Talanti celebrate their beast. They've named him Uruk, and they dedicate entire days to his honor. The Talanti also follows an oath of honor. They believe that all actions must benefit Uruk, and anyone who stands in the way of their connection will be fed straight to the beast. It's the simplest way.
Other than that, the Talanti are pretty peaceful. Typically, there is at least one craftsman living amongst the tribe who will make small tools out of bones. The most common career, however, is to maintain the integrity of the wooden platforms that the Talanti live on, as they are in need of constant surveillance.
There is only one group of Talanti in existence, and as far as they know, they are the only humans in existence. The tribe consists of about 40 members. That's all they need to keep themselves running, and expanding much more would require people to move off of the tarrasque which is not an option for them.
The Talanti also love collecting treasure. They don't like keeping it quite as much. It's ancient tradition for them to accumulate as many symbols of wealth as possible, and as the ages have passed, these symbols have morphed to represent good fortune instead. They like anything shiny, and they specifically love gold. That being said, the limited space on Uruk's back have forced them to let go of their hoarder lifestyle. Every month, they have a "gratefulness day," where they throw all of their gold into the sand.