It amazes Zuko how quickly the palace closes in on itself to repair the damage. Servants materialize within days to clear away the blood and the cinders and the rubble. Before Zuko can wrap his mind around Ozai's death, Azula's death, the Avatar's victory, his own survival, the first formal ceremony has begun.
To cleanse. To purify. To bring fortune to his reign.
Zuko cringes inside himself. He isn't sure if they're trying to cleanse away his own failures and weaknesses or the shame of Ozai's defeat or the memory of a hundred years of war.
With fields of battle still smoldering they invest him with the powers and obligations of the Fire Lord. They perform the sacred rites while Zuko wears the sacred vestments and assumes the sacred throne. Throughout the endless litany of vows and blessings he sits imperious and silent behind a wall of flame.
Decades ago there had been feasts and dances. Under Azulon all formal ceremonies lost their frivolity and took on a military precision. For Zuko, the endless, dull beat of the drums and the drone of the horns sound like a funeral march.
Zuko feels like a fraud. Ozai was the Fire Lord. Azula was the Fire Lord. Zuko is still the outcast prince who returned only to bring ruin to their house.
But the courtiers don't see that. The great families don't care who ascends the throne as long as they receive their due. Zuko helped to defeat Ozai, and Zuko is the Fire Prince, direct heir to the throne. It's no question.