1. Prelude

"No!" a male voice shouted angrily. "Too weak! You're too weak, Zaya. Get up, and do it again."

An eight-year-old girl was lying on the ground of a huge garden, under the scorching sun of summer. Zaya was laying on her stomach, bent in half, her face touching the burning concrete. Every limb of her body ached so badly that she couldn't even move an inch. As she was lying lifeless in the immense courtyard, she saw a pair of brown boots walking over and stopping in front of her amber eyes. She looked up, her vision blurred from exhaustion. The furious face of her father cleared up little by little, and she could discern his thick, dark brown eyebrows knitted together.

"Get up, Zaya. The enemy won't wait for you to be back on your feet to attack again."

With great effort, enduring the extreme pain coming from her stomach, little Zaya lifted herself, and, swaying slightly on her small feet, she stood. She grabbed the gleaming sword that was lying next to her, and took a fighting stance, as steady as she could manage.

"Don't deceive me again," her father said as he attacked her.

Her father brandished his Dadao sword right at her face. It had a curved blade and was longer than her Jian sword, which was a more common weapon. He could touch her more easily thanks to the longer length, and his more refined technique. Zaya was already out of energy, so even dodging her father's continuous strikes took a huge toll on her body. She couldn't hit back even if she found an opening – not that there were any – and her wrist started to tire from holding the heavy sword.

Her father, Zimu, was an influential man in Republic City. He founded his empire through metallurgy, producing and selling steel around the world, for civilians and militaries – the swords they were using were personally forged by him. He established his mansion, called the Zimu's estate by others, in the wealthiest district of Republic City where he lived with his wife, Neiko, and their only daughter, Zaya, as well as an army of servants.

Behind his official activities, Zimu was also the boss of one of the most wanted criminal organizations of the city, the Agni Kai Triad. It was a crime group composed of only firebenders, as opposed to the other two big organizations, the Red Monsoon, formed by only waterbenders, and the Triple Threat which regrouped firebenders, waterbenders and earthbenders.

Zimu was originally born in the Fire Nation, in a noble family. His ancestors have been serving the Fire Lord for many generations, until Zuko became the sovereign. He then banished Zimu's family while he was only eight years old because they were associated with a group of rebels.

In one night, Zimu lost everything: his parents, who couldn't stand being exiled, his home and his luxurious life. He embarked alone in a boat that brought him to the newly created nation by the Avatar, the United Republic of Nations. He arrived in Republic City empty-handed, with only a small backpack containing a few clothes. He wandered in the streets for two years, stealing food to survive.

One day, he snatched a bun from a random guy on the streets, and ran away. Usually, people didn't run after him for a small bun, but that man started chasing him. The man cornered him in a dead end, and claimed his food back. But, Zimu didn't hand it over, and attacked him instead. The man was wiser and stronger than a ten-year-old stray kid, so a single kick was enough to send Zimu flying. The young thief dropped the bun on the ground, and the man walked over slowly and picked it up. He blew on it, and took a big bite in front of Zimu.

The only thing Zimu remembered before falling unconscious on the dirty ground was the corners of the man's lips rising in an evil smile. The next thing he knew, he was sleeping in a bed, in a small room. When he woke up, the man was sitting on a chair near the bed, peeling an apple. He greeted him with his deep voice, in a normal tone, as if nothing had happened between them. He then said that he found Zimu really interesting for trying to attack him earlier, even though it was futile. The man introduced himself to Zimu; he was the leader of the Agni Kai Triad. He offered Zimu to join his group because he thought that Zimu had a lot of potential.

Indeed, he wasn't mistaken. Zimu was a really smart boy, on top of being an excellent fighter. As a son of a noble family of the Fire Nation, he was trained in the arts of firebending and swordsmanship by the best teachers. Zimu quickly rose through the ranks, and five years later, at only fifteen, he became the right-hand man of the boss. When Zimu reached twenty years old, a tragic turf war broke out between the Agni Kai Triad and the Triple Threat, leading to the death of the Agni Kai gang's boss. Seeing his mentor lying on the ground, soaked in a ruby-colored puddle, Zimu lost his composure, bursting into tears. The leader's dying wish was to leave the Agni Kai Triad in his protégé's hands, making Zimu the youngest boss of all the mafias in Republic City.

However, despite spending more time in Republic City than in the Fire Nation, Zimu never forgot the humiliation he suffered because of Fire Lord Zuko. Once he became the boss of the Agni Kai Triad, he decided to take revenge on Zuko. The opportunity came many years later, a few days after his wife had given birth to their daughter. News from his spies in the Fire Nation had informed him that the Fire Lord was blessed with a grandson a few months ago. That was the key to the success of his revenge. The time hadn't come yet, but it would in the future, and he needed to be ready. That day, Zimu decided that he would train his daughter in order for her to restore his honor.

He began his intense training as soon as Zaya could walk steadily. Luckily for him, his daughter was a firebender like him, and not a non-bender like his wife Neiko. He taught the young child his perfect technique in firebending, as well as royal-style swordsmanship that had been handed down for generations in his family. Zaya was a smart girl, and a fast learner. She mastered firebending in no time, and wielded her sword as skillfully as soldiers. However, she still couldn't defeat her father. Zimu was an excellent swordsman, so he was really strict on her. He needed her to become the best in order to defeat Zuko, who was well-trained in both firebending and swordsmanship.

While her husband and daughter were training hard in the back garden, Neiko was preparing snacks for them to eat after their practice. Neiko was a regular citizen, born in Republic City, from a family that ran a restaurant. However, business didn't go well, and her parents had to borrow money from the Agni Kai Triad. That was the beginning of their nightmare. High interests kept adding to the original sum they borrowed, and loan sharks would come everyday to claim the money. In the end, her parents couldn't pay anymore, and she became an orphan overnight. But criminals didn't have a heart, and they made her work for them, giving her ungrateful tasks.

Neiko first met Zimu when they were sixteen. She had been working for the Agni Kai Triad for a year. She often saw him accompanying the boss wherever he went. One day, one of the men harassed her at the headquarters, but no one would bother to help an insignificant servant like her. Zimu was different. He tried to stop the man, but the latter didn't listen to him. He threw his fist to punch Zimu in the face, but the young man was agile, and easily dodged him. They engaged in a fierce fight, and were finally stopped by the boss. Neiko tended to his wounds, and the two of them grew closer little by little after that incident.

Marrying the boss of a mafia gang didn't mean that you had to take part in shady activities. Neiko didn't concern herself with what her husband was doing with the Agni Kai Triad. Instead, she devoted herself to the official face of Zimu's company: metallurgy. She was the one managing everything, from the extraction of the coal to be transformed to the delivery of the steel. Their main clients were the Metalbending Police Department and other industrialists such as Hiroshi Sato's Future Industries. Despite being very busy, she still took time to play with Zaya, loving her tenderly. Neiko didn't approve of Zimu's criminal activities, and managed to change his modus operandi, especially when it came to debt collecting.

Walking towards the garden, Neiko put a plate of fresh red beans buns on a stone table located under the shade of a large ginkgo tree, on the side of the courtyard. She sat on a chair, and watched her beloved husband and daughter fight fiercely in the middle of summer, with a tender smile on her glossy lips. Zaya got a few scratches on her small body, mostly on the arms and legs. Despite still being a child, Zaya's endurance could match with her father's, and her stubbornness – that she inherited from him – drove her to go past her limits. Zaya was an ordinary little girl if you put aside the fact that she could already firebend and wield swords since the age of five. Just like her mother, she was cheerful, and always smiled with an honest grin, showing her missing tooth right in the middle of her mouth.

Exhausted, but not wanting to give up, Zaya rolled on the ground one more time after receiving a kick from her father. She got up right away, using her sword to stand on her feet. She looked straight into her father's bronze eyes, and after taking a deep breath, ran at full speed, using up all the energy she had left. She brandished her sword at her father, and aimed at his right shoulder. Zimu saw right through her, and parried her attack with his sword. However, the next thing he knew, he had fallen to the ground and Zaya was pointing her sword at his neck, with a triumphant face.

Zaya actually fooled her dad by letting him think she was aiming at his shoulder, only to attack his blind spot. As the Dadao sword was a longer and heavier sword, Zimu had to use both of his hands to swing it, and Zaya took advantage of that. She knew her father would easily block her attack with his sword. To stop her, Zimu needed to raise both of his arms. By lifting his left arm, he created a blind spot on his left side. Zaya was small, and agile. In a deft motion, she used the strength of the collision of both of their swords to turn around and land a kick on her father's left sides. Surprised by the pain, Zimu bent over, backpedaling, and fell to the ground. He looked up at his daughter's happy face, and smiled, satisfied.

"Good," he said, as he took the hand she was extending to help him stand back. "You've worked well. Your mother prepared snacks for you. You can go eat." He patted her head tenderly, and watched her rush to Neiko. His daughter was strong. She would be able to accomplish her mission when she got older. The corner of his lips slightly raised. Zimu was pulled out of his evil thoughts by Zaya's voice.

"Dad!" she called him. "Come eat with us!"

"I'm coming, sweetie," he answered, before diabolically snickering to himself, "Be careful, Zuko. Your nightmare is growing stronger. The time of your end is near."