Avatar: The Last Airbender is indeed an original story. It has its own distinct style and narrative that sets it apart. The combination of elements like bending powers, diverse characters, and complex story arcs make it a one-of-a-kind creation.
Definitely not real. It's a fantasy world crafted with unique characters and magical elements that exist only in the realm of imagination and storytelling.
In Avatar: The Last Airbender fanfiction, a blind OC could have a really interesting backstory. Maybe they were born blind in a tribe where physical ability in bending was highly prized. This could lead to them being an outcast at first. But as the story progresses, their unique perspective and abilities could prove invaluable. They might be able to sense an approaching enemy before anyone else, or have a special connection to the spirit world that is enhanced by their lack of sight.