Epilogue
When Sokka is closest to the Order of the White Lotus, it could be said that he is furthest from all his friends. Not, to be clear, that they do not care for him. Not, to be clear, that he does not care for them, and deeply. But rather, after so much time surrounded by so many masters of the elements to which he could never compete, it would only be natural that he would eventually look elsewhere for understanding, and to be understood.
Piando saw this, Piando understood this, and the most suspicious might say that Piando encouraged this. But Piando merely gave Sokka the opportunity to enter a world in which the flexibility of the elements was far secondary to the flexibility of the mind.
The Order of the White Lotus would be necessary, as it always had been. The Avatar is only one person, however powerful. One force for Balance in the World, the last resort of Nature when all else had failed. The Order, the Order could prevent it from failing in the first place, not through armies and bending but through wisdom, whispers, and knowledge of how to use the universal skills.
Piando saw a boy, self-estranged and powerless, but with the desire and the potential to help the world. Piando did not make him do this: Piando merely made Sokka aware of what he could do.
After the War, Sokka continued his travels, alone this time. After returning to Master Piando's estate to finish his training there, Sokka traveled the world, learning with many other masters, and mastering many other skills. In between times of helping his friends and the Avatar, Sokka became a familiar, if never permanent, presence in many of the highest circles of the lands, as often seen in the halls of the Earth Kingdom as behind the Throne of Fire or in the Ice Palace of the North, a man with the ear and trust of all the wise rulers of the lands. When Sokka died of old age, not even his wife or sister knew of his decades-long position as Grandmaster of the Order, or of his indispensable role in shaping and preserving the unique Age of Peace that lasted after the end of the War.