The Sun Warriors are the original civilization that first discovered firebending from the dragons. The precursors to the modern-day Fire Nation, most believed they had died out thousands of years ago, but they are still alive and living in secrecy near the ruins of their once-thriving city.
The Sun Warriors revere and guard the two great firebending masters, Ran and Shaw, one of which is a red dragon and the other blue. These dragons pass on the secrets of firebending by breathing a multicolored flame over those they deem worthy.
The Sun Warriors developed all of the original firebending forms, such as the Dancing Dragon, but their philosophy is radically different from the present-day Fire Nation. While most consider firebending to be an instrument of destruction fueled by rage and hate, the Sun Warriors believe it represents life and energy, as if there was a sun within every firebender. They are keepers of the Eternal Flame, a great fire that is said to be the first given to mankind by the dragons.
The Sun Warriors prefer to keep their society secret to the outside world; therefore, anyone who discovers their tribe and is deemed worthy to know the nature of firebending is instructed to never reveal the existence of the tribe to anybody else. Aang and Zuko kept their word, seeing that while they mentioned the learned form, they made no mention about the supposedly lost civilization.
The culture of the Sun Warriors may be partially based on the sun-worshiping Aztecs and Mayans, American civilizations in pre-Columbian Mesoamerica. The Aztecs and Mayans were sun worshipers and careful observers of astrological movement. One of the first buildings shown resembles the real life pyramids of these civilizations.
The entire conceptual schema of the Sun Warriors, their "lost city", their civilization, and their practices bear resemblance to the works of Robert E. Howard, the creator of Conan the Barbarian. Numerous nods to Howard's oeuvre can be perceived throughout the series.
The Sun Warriors are heavily inspired by Southeast Asian cultures.
The primary ziggurat in the Sun Warrior compound bears a striking resemblance to the Candi Sukuh in Indonesia. Step Pyramid style ziggurats also exist in Mesopotamian and Mesoamerican architecture.
The Sun Warrior compound includes architecture inspired by other Southeast Asian landmarks such as the Angkor Wat and the Phanom Rung.
The tribe's clothing is reminiscent of traditional Southeast Asian warrior attire, particularly the headdress of the leader, which resembled Iban feather headdresses, and their pants resemble the Indian dhoti.
The Sun Warriors' chants at the Dragon Ceremony sound similar to the chants at the end credits of Avatar.
The way most Sun Warriors wear their hair resembles Zuko's ponytail in the first book.
Uncle Iroh had previous knowledge of this tribe, and it was the origin of his nickname, "The Dragon of the West".
Despite their isolation and secrecy, they have a surprisingly high amount of knowledge of current events.
They are some of the only firebenders shown whose bending had not been distorted by rage and hate like the firebenders during the Hundred Year War.