So in Fullmetal Alchemist, or at least Brotherhood, we saw Pride devour Gluttony and take his powers for himself. Imagine if you had a single Homunculus with the combined powers and energy of all 7.
And in the other corner, we have the Avatar (OC or pick your favorite) with every form of bending ever shown (blood, lightning, metal, etc) all at peak performance.
Who wins?