Ozai was dead. Ozai was dead, and Azula was dead, and there was no one in the country to make Fire Lord. Someone suggested making the Honorable Lizheh, Admiral of the Bureaucracy, Fire Lord, but the wizened man sniffed and said that in all of the recorded history of the Fire Nation, there had never been one not of Dragon blood on the throne; such things were simply not done.
And so they went to find the Exile Prince, who looked at the messenger incredulously for a moment before sighing. He went into his office, fetched pen and paper, and made the man witness his official abdication. When the messenger, in a faltering voice, asked the man Formerly-Known-As-Crown-Prince Zuko, who the hell was going to run the country now, begging your pardon, m'lord, being as there's no one else, the currently Not-Prince-Just-Zuko grinned slyly and said, there is someone else, and he has prior claim. Now get out of my shop before you scare away any more customers.
And so it was that the Honorable Lizheh went to the country estate outside the village of Usahagi (because clearly messengers would not be able to be patient and persistent enough, and Lizheh had had nearly a century to perfect both patience and persistence), and knocked on the front door, and asked his old friend, formerly General, formerly Crown Prince, always Dragon of the West Iroh if he would please come back and be Fire Lord, because there really wasn't anyone else left to do the job. Please.
And Iroh closed his eyes, and sipped his tea for a moment (wintergreen, those dear children from the South Pole had sent it to him) before sighing and saying, "I am old. I am retired. This old man wants nothing more than to drink his tea and play Pai Sho with other old men in the afternoon sun, and as I recall, there is a spry young man who is perfectly qualified for the job. You know, my nephew?"
And the Honorable Lizheh said, rather quickly, "Yes, only he renounced his claim and then sold his shop and now he's... goneintohidinguntilwepromisetoleavehimaloneaboutit."
And Iroh took another sip of his (really very exquisite) tea, and said softly, deliberately, "The little weaselbat beat me to it."
In the end, the Honorable High Bureaucrat Lizheh returned to the capital with the Crown-Prince-Soon-To-Be-Fire-Lord-Just-As-Fast-As-We-Can-Jam-A-Crown-On-His-Head-Before-He-Changes-His-Mind Iroh in tow.
And two weeks after his coronation, one of the (ancient, wizened) bureaucrats turned to Fire Lord Iroh and said, "Don't you think it's high time you got married, young man? This country needs an heir."
A/N: Ahah... again with the so late it's early posting... ohhhh Iroh. This is me experimenting with style. Sorry.