She doesn't grow out of it. Azula is six, and 'feeds' the turtle-ducks with thrown rocks. A part of Zuko knows why, and watches with calculating eyes. He is Ursa's favorite child, and takes all the love the woman has to give. Azula is jealous; jealous of Zuko, jealous of the turtle-ducks, and even negative attention is better than nothing.
But the rest of him, the eight year old boy, doesn't understand why his sister hates him, and wishes he could make everything better. Azula likes firebending; he is indifferent, so he can give her that, and complement her ability.
Azula shoves the door to Zuko's room open, and swaggers in. "Dad's going to kill you," she says, hiding fear beneath a gloat. "He really is."
Zuko stares at her, eyes shadowed and there-not-there. She hides a flinch, and smirks. Dad looks at her like that, through her, like she doesn't exist.
It's a relief when Mom comes and drags her away. "Dad wants to be the Fire Lord," she tells Mom.
Mom stares at Azula, and sends her to bed. Azula goes, but not before seeing Mom take a knife from the wall.
She saved Zuko, and everything changes.
When he dreams, he has everything. Memories, mask, swords- understanding. He dreams that he walks through walls, to check on Azula, who shivers in her sleep. He pulls the blankets up over her shoulders, and leaves, to wander the palace grounds, looking for someone who doesn't want to be found.
Zuko wakes up, and goes down to breakfast. Azula complains about drafts in her room, and how it shouldn't get so cold in summer, and tells the servants to pile her bed high with extra blankets. Their father sits at the head of the table, silent and dismissive, not listening.
Azula is away at school, and it's a terrible, horrible relief. Her creep of a brother isn't with her- oh, sometimes he's normal, but most of the time he very much is not- and there are no reminders of her absent mother. Her father... Well, she loves him. She does. And he loves her, because she is strong, and smart, and powerful.
But school is very lonely. There are two girls here that no one talks to; Ty Lee, who wears pink and talks about seeing auras, and Mai, who never changes expression.
She talks to them. They let her.
She brings her friends home with her. Their parents allow it; their children are friends with the princess, and that is very good, politically.
Mai doesn't notice that Zuko is wrong inside, and instead seems to like spending more time with him than with Azula. Ty Lee, at least, took one look at Zuko and blanched.
Ty Lee later confides that Zuko's aura is... off. It's blue, and black, and not connected with his body at all.
Azula sniffs, and pushes Ty Lee over into the dirt. She doesn't need to hear any aura nonsense, to know Zuko's just creepy.
