Ok actually, after analyzing your story, I've convinced the universe and power level of your characters are too much for the one's in Avatar: Macai's Journey (a fanon spinoff of Avatar: The Last Airbender). While AMJ characters are awesome and epic, they are only OP to a certain extent (as in for their universe like the Jedi are in the 2003 Clone Wars series). A bit more like a Captain America, Batman, or maybe a level 7 in terms of fictional power. Your characters seem to be around level 8-9. They have so many wild abilities while most characters from AMJ have a set of more tangible, set, and measurable powers.
Without some situational spiritual amp or something, my MC Macai would be toast. Now if he got an amp from the light spirits, he could be as strong as he needs to be because spirits can reach whatever level and have no physical bounds (when compared to physical beings). With that being said, if Macai received such an amp, he'd have the advantage of ranged attacks and would then obliterate this character because he fights with white flames which are blinding in nature.
The characters from your story seem to rely on physical and melee attacks so that would be an important edge. But outside of that I see guys in your universe with insane super speed, teleportation, super strength, and other powers that seem to come out of nowhere. People just get stronger when the situation demands it (I know that is somewhat because of the themes of the series).
In AMJ, people's skills and powers develop more slowly. They are meant to mirror reality (like pro-Boxing, MMA, Kickboxing, some of the grounded Star Wars works) in the sense that people have different fighting styles, strengths, weaknesses, etc. Any changes are not immediate and must be worked toward. With all that being said, your tale is very impressive.