As 8 year old harry potter slept in the small, dusty and cramped cupboard under the stairs, battered and bruised from getting beaten up by his cousin Dudley, and with a burn on his hand from cooking for his foster family, the dursleys, a dragon from the spirit world flew, invisible, into the cupboard and started to breath a stream of fire all the colours of the rainbow on harry, transporting him to the courtyard of the fire nations royal palace, whilst transforming Harry's magical powers into firebending skill, healing him of all injuries, apart from his lightning shaped scar, and making him the same age as his sister to be, Azula.
When he woke up, he was in a comfortable bed in a room decorated in the colours of red, gold and black. There was a girl with long black hair and piercing amber eyes.
"Who are you, where am I?" asked harry
"calm down, calm down, ok, my names Azula, princess of the fire nation, daughter of fire lord Ozai, and a firebending prodigy, but you can call me Azula" replied Azula
"Ok, hello Azula, my names harry, but where am i?" harry wondered
"Oh that's easy, the is the fire nation royal palace" said Azula "come on, let's see if you can firebend"
When they arrived at the training ground, Azula taught harry a basic firebending technique and, after a few trial runs, harry managed to perform the technique.
Nothing much really happened in the next 3 years; harry read books about lore and history, as well as scrolls about firebending. He also spared with Azula every morning, so that they both could increase their firebending skills to the point where azula's fire was blue. Another thing they did a lot was tease their older brother, Zuko, calling him zuzu and dumdum.
One day, Zuko went to a war meeting and spoke out against a general and was challenged to an Agni kai, but instead of fighting the general he had to fight his father, the fire lord. But because Zuko refused to fight, he got burnt on his left eye and was banished from the kingdom. He could only restore his honour by finding the avatar, who had been missing for 100 years. Azula and harry looked on their brother, getting burnt and they smiled. They knew azula was now the crown princess.