Chapter 1

Athena

It had been a year since Splinter and his "sons" have begun to live in the sewers and had undergone the mutation that made them complete outcasts in the human world. Although it was difficult to adjust at first, the rat eventually grew to accept his new life, since his old one had been destroyed by one of great evil. To protect his sons from the fate that took Splinter's master, Hamato Yoshi's, life; Splinter decided when the turtles were old enough, he would teach them Ninjitsu, the way of the shadow ninja.

However, he did not know that there would be five students instead of four.

It was a brisk December day in New York City and Splinter was topside in an alley, gathering food for his four five-year-old sons and himself. Normally, Splinter never left the sewers unless it was an emergency or for food. Fortunately for Splinter, it was the latter. After finding and gathering food from bountiful dumpsters, Splinter made his way to the manhole when he heard a cough coming from a nearby dumpster, making the rat jump in a defensive stance.

Cautiously, the rat approached the dumpster, preparing for any kind of attack. When none came, he lifted the dumpster's lid and gasped in shock.

Inside the dumpster was a woman in her mid-twenties. Her black hair looked like it had been severed hastily. She was dressed in what seemed to be some sort of priestess kimono, except the pants were green and blue and her top was red and yellow. And on her stomach was a very deep wound.

But before Splinter could do anything, the woman opened her smoky grey eyes. She was a bit startled by the sight of him, but was quickly relived. As if she was waiting for him. She then reached for a cardboard box next to her and removed it to reveal a cradle-basket.

In the basket was an infant with silver hair wrapped in a white blanket, sleeping peacefully. It continued to do so as the woman weakly lifted the basket and handed it to Splinter.

"Please," she spoke.

"Please protect her while I'm gone. She is what I died for."

As Splinter grabbed the basket, the woman's hands fell, the last of her breath leaving her cold body.

Splinter gave the woman a proper cementation in the junkyard just as he did for his own master. As he collected the ashes into a green, red, blue and yellow urn, his thoughts went to the child she had entrusted to him.

What should he do?

Should he abandon her to a human orphanage in hopes that a good family would adopt her? Or should he raise her alongside his sons? What would his sons think if he brought her home?

As he looked at the sleeping girl in the basket, he then made his choice.

One hour later…

Splinter quietly entered the burrow as he made sure that his sons' naps were not disturbed. He also did not want his newfound daughter to wake up and alert the five-year olds. He wanted them to meet her one by one.

"F-father?"

Speaking of which, Splinter turned to an opening and spotted a turtle boy holding a blue blanket in his hand. Placing a finger in a "shush" motion, Splinter motioned the boy to come closer.

"Come, Leonardo. There is someone I want you to meet."

Leonardo walked over to his adoptive father, confused. When he was close enough, Leo watch as Splinter brought down a basket he had placed on the table earlier. Leo looked inside and saw the silver-haired infant, still sleeping.

Leo's eyes widen at the sight of the child. Looking at Splinter, he asked "Who is this?"

Splinter gave a gentle smile as he introduced the child.

"This is your new younger sister, Leonardo. I have found her while I was gathering food."

Leo was shocked and thrilled at the thought of having a younger sister. Even though he was already an older brother, he had never thought he would ever have a sister.

As he gazed at the girl, Leo asked, "What is her name?"

Splinter knew his sons would ask if he had named their sister, so he had searched for a name that was right for her. He hadn't found any Renaissance artists that had that right name, so he searched until he came across a book on foreign gods and goddesses.

"Her name is Athena. It is the name of the Greek goddess of wisdom."

Leo looked at Splinter, then at Athena.

Wisdom…it suited her with her closed eyes. However, those eyes didn't remain closed for long. Her eyes fluttered open, revealing shades of blue and green. The eyes confirmed that the name was perfect, as she saw the two figures that were her father and older brother, identifying them as friendly.

Splinter then looked at Leo. "Go and finish your nap, my son. When you and your brothers wake, I want you to tell them about Athena and make sure that they don't frighten her."

Leo nodded as he whispered to his sister. "Nice to meet you, Athena. I'm you're big brother, Leonardo."

Athena gave a curious look before she gave him an open-mouthed smile as he returned to his room.

An hour later, the four boys woke up and Leo explained to them about their new sister.

Michelangelo was happy that he was finally an older brother.

Donatello couldn't wait to teach Athena about science when they were old enough.

Raphael, however, was cautious, despite Splinter's say-so. Then again, Raph was always the distrustful one.

Once Leo told Splinter that the others were awake, the old rat nodded, signaling them to come over. As told by Leo, the boys walked calmly over to the rat and the infant, but that didn't mean that they weren't excited.

"Aww, she's cute." Mikey cooed.

"Where did you find her, father?" Donny asked.

But Splinter knew that it would be a bad idea if they knew what had happened at this age. For now, he just simply spoke.

"That is a story for another time, my sons. All I can say is that fate brought her to our family."

He then noticed that Raph was still cautious around the baby, so he asked the red bandana turtle boy to come closer. "Come, Raphael. Say hello to your younger sister."

Although he was indifferent, the turtle spoke. "Hey."

Athena looked up at her red brother and gave a chuckle, grabbing his outreached hand by his finger.

The boy was stunned for a moment, but finally gave in, chuckling. "Heh, you got a strong grip, sis."

Splinter was relieved that all of his sons now happily accepted the child as one of their own. Over the next year, he watched as his sons continued to bond with Athena.

Mikey always wanted to hold Athena whenever he could. Each time he was allowed to hold her, he would say, "Never fear. Your big brother, The Turtle Titan, is here. Come, my tiny sidekick. Let us catch another batch of bad guys today." Making Athena smile ended up as one of his favorite pastimes.

Donny also had a few experiences with his little sister. Once, he found an unusual box floating in the sewers and brought it home. Once he found it had gears inside, the boy worked on fixing it, not caring what it was. One day, Donny was called for lunch when Athena crawled into the workshop.

A curious child, she explored her brother's room until she spotted the box on the desk. Crawling up some empty milk crates, Athena made her way up to the top of the desk and gazed at the box. She picked up the box and noticed a key sticking out of the side. It took a while, but the baby managed to turn the key right. Once she turned it as hard as she could, she let it go and lifted the lid. To her surprise, it started to make music.

Donny came back to look for Athena when he saw her on the desk, watching the unusual box.

"Athena! What are you doing up there?" He asked in fear and shock. But he became silent as he listened to the music. It wasn't long before he too was entranced by the music.

Noticing that his son and daughter had been gone for a while, Splinter began to look around until he, too, heard the music. Looking into the purple clad turtle's room, he found both children, looking at the source of the sound.

"Donatello." He spoke, startling the turtle.

The rat then took notice on his daughter's fascination with the box.

Realizing what was going on, the rat looked at the boy.

"She's been like that since I got here. Is she ok, father?"

"She is fine, Donatello. It seems that we have a musician in the family."

Donny was confused for a moment, and then realized what the rat meant.

As soon as the music box was done, Athena soon found herself in her father's arms, tired. As Splinter left with the child, Donny looked at the music box and smiled to himself. Athena could figure out some things that he could not. And that made Donny both jealous and proud.

The rat also witness Raphael spending time with Athena, teaching her on how to be a tough kid. But what made Raph proud was when his sister took her first steps. Using the couch as a support, Athena slowly made her way to Raph until he was able to keep her from falling without moving from his own spot.

"Atta girl, sis."

And Leo had a similar experience another year later, when he heard Athena speak.

"L-Leo."

He looked at Athena in her basket, startled.

"Athena?"

The baby looked at him, smiling. "Leo. Leo."

No one could have had a brighter smile than Leo.

As the years passed, Athena grew along with her brothers. When she turned five, Splinter began to teach her Ninjitsu, giving a pair of small metal fans as weapons. And all seemed peaceful for the unusual family, until one fateful night.

I do not own TMNT, or Avatar: the last Airbender. Athena is my oc. I do not intend for a brother-sister romance here. She is just their sister.

In the next chapter, which is the start of the TMNT 2003 series, the turtles are 15 and Athena is 10.

Review, hold the flames please.