What is the original source of firebending? In The Firebending Masters, the true source seems to be at least 3 different, possible things: the Sun, the dragons, and the fire (the life and energy) of the soul. So which is it?
In The Firebending Masters, when Zuko's firebending is so weak due to changing sides, he and Aang go off to the ancient Sun Warriors civilization, despite both them and the dragons being supposedly extinct. There is a good argument for which of these 3 are the true source: for the sun, firebenders draw their power from it, are weaker at night, and cannot bend at all during a solar eclipse; for the dragons, they were the "original" firebenders until the Sun Warriors became the first human firebenders after understanding the connection between the sun, the dragons, and the fire of soul; for the fire of the soul, after Aang learns from the dragons, he says, "I thought firebending was destruction.....But now I know what it really is ... it's energy, and life", and Zuko says, "It's like the Sun, but inside of you......I lost sight of my inner fire."
Which would you say is the true original source? A person's soul's fire/life/energy, the dragons, or simply the sun?
I do believe one thing. It might be a dopey headcanon, but Avatar Wan was the one who developed "the dancing dragon form." Ain't no good reason he couldn't have been a Sun Warrior. It could be why the Sun Warrior city is in ruins. Wan lead a rebellion to crush their tyrannical leaders and realized it was a huge mistake.