"Avatar: The Last Airbender" explores the theme of destiny versus choice through the character of Aang, the Avatar. Aang is faced with the destiny of being the one to save the world, as it is foretold in the Avatar cycle. However, throughout the series, he grapples with the idea of whether he should follow his predetermined path or make his own choices. This internal conflict highlights the balance between fate and free will, ultimately showing that while destiny may set a path, it is ultimately up to the individual to choose how to navigate it.