Okay, I cheated. This one is Azula-Zuko, because I love her for entirely different reasons. Set pre-show.

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“They’re MINE,” Zuko barked at the small figure crouched in front of him on the playroom floor, her chubby chin held charmingly on her knees. He was clutching the object of her desire to his chest so hard the tips of his fingers were white—a lacquer box of almond-paste candy, dyed and sculpted into fantastical animal shapes. Zuko was not a particularly cultured appreciator of the culinary arts, and to him they were special for another reason—they were a gift from Uncle Iroh, before he left on campaign across the Inner Sea.

“Please?” wheedled Azula.

“Go away. You ate yours already. “

Azula got to her feet, her sweetest and most winning smile in place on her lips, and wandered around behind the table at which Zuko sat. She wrapped her arms around his shoulders and rested her head lightly against the back of his neck. “You’re nice to everyone else, Zuzu. Why aren’t you nice to me?”

“Stop calling me that, Azula. You’re five. You’re not a baby anymore,” he said, and shrugged out of her loose grip. “Go bug Mom if you’re hungry.”

“Fine…” she sighed, and straightened. Zuko glared at her. As he watched, her smile shifted off balance, all the sweetness pouring off in a flood. She slid her feet wide and stiffened her small hands, eyes fixed on the small lamp that illuminated the two armies of clay soldiers Zuko had spread out to do battle.

“Azula, don’t!” he hissed, dropping the box and bolting to his feet to grab her wrists.

He wasn't fast enough. With a sweep of her hand she drew a thin stream of the lamp flame out of its paper walls to brush in whisper-close spirals around the loose cloth of her sleeve. It flared ember red and charred immediately. She looked straight at him, then screamed as loudly as she could and collapsed to the floor in tears.

Ursa and one of her maids swept into the room a split second later. She took in the scene with wide eyes, her daughter curled up on the floor clutching her bare arm, smeared with ash, Zuko crouching over her. His mother’s temper was difficult to kindle, but when lit it burned fiercely white-hot. She grabbed him by one arm and pulled him roughly away, her long nails digging painfully into his skin.

“You will never do that again!”

“But Mom, I…”

“NEVER!”

“But she…”

“Cheza, take him to my husband and explain what has happened here. Prince Ozai will see to his punishment. I make no call for leniency.”

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Later that night, Azula kicked the sheets off her bed and padded silently into the playroom. The box was still there, lying atop several porcelain Earthbenders broken to pieces by its impact. She slid the top away and selected a brilliant green sparrowkeet from its bed of tissue, pausing for a moment to admire it in the scant moonlight. With a satisfied grin, she popped it into her mouth and bit off its head.