It was more apparent as he kept getting older. He awoke from dreams that he knew had been memories once upon a time, expecting to see greens and stone, or blues and ice, instead of scarlet and lava. He never forgot he was the Avatar, but it worried his attendants that it stopped mattering which one.
He knew he was dead when the Avatar Kyoshi knelt by his bedside when he awoke. The room behind her was covered in the white of mourning.
"What now?" the Avatar asked.
"We wait," the Avatar answered. "Soon an Airbending child will be born, and the dance will continue."