<p>We may not exactly know when the Sun Warrior civilization came to be, but we know that they learned the Dancing Dragon firebending form from dragons.
</p><p>Could it be possible, however, that Wan was the "inventor" of the form, as he was [essentially] the first human to use firebending as an extension of his body, rather than just blasting fire around to attack spirits and obtain food (as mentioned in a brief narration by the huntsman)? We see him learning the technique from a white dragon while living in the Spirit Wilds for two years, followed by the mentioned narration by the huntsman, marveling over Wan's use of fire like no one has done before.
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