She was born for him. No, really, she was. Her parents, Aishiteru and Katon, were the parents of Nejimaru and Akita Uchiha. Twins, they were put on separate genin teams- Nejimaru was teamed with their first cousin, Katsu Sarutobi and Torifu Akimichi's son Taiga, and completed many missions together with their Jonin-sensei Ichiro Mitokado. Akita was placed with Hizashi Hyuuga and apprentice med-nin Kaoru Daisho, an older Genin who had failed the first test and been apprenticed for a few years. He was completing the Genin requirements to be field medic, and they were under the direction of Sakumo Hatake, the White Fang. It was Akita who informed her parents
"Kakashi-chans' mother died birthing him." Aishiteru knew that Sakumo would have his hands full, and Katon agreed when she suggested a final child to be raised as closely with Kakashi as possible.
She was born nearly precisely a year after him. When Akita proudly showed off her sister across the village, people would ask if she was looking for betrothals. The impish girl would laugh and say breezily
"No, no, she's promised to sensei's puppy!" This was of course, the first Sakumo had heard of this. However, over the next few years, as she became more mobile, she toddled after Kakashi on chubby legs, learning Kenjutsu and other weapons from her mother, but otherwise content to sit and watch Kakashi, who perked up whenever the younger child came by. Gradually, as she became a port in the storm more than the semi-captive audience of the earlier years, Sakumo expressed a concern that she wasn't being properly socialized. Katon snorted and retorted
"Have you tried getting her to do something that doesn't involve Kakashi? She plants her feet and waves her bokken around!"
Once Kakashi realized that he was her only real company, he resolved to take her to meet his team- after all, she had saved his father from depression by insisting Sakumo-ji come to dinner, and he must watch her practice. The kicker, the younger Hatake mused, was when she had kicked and fussed for ice cream, only to demand
"Sakumo-ji, you are going to protect Konoha, right? Neechan says that you are one of the best Jonin in Konoha, and Aniki says you're stronger than his silly Ichiro-sensei, 'cause you're The White Fang, with the strongest Will of Fire he's ever seen!" Sakumo had brightened, and when he'd glanced at Kakashi only to wilt, the Hatake-puppy's best friends' stomp on his toes was hidden by the table. Kakashi scrambled to add
"She's right, Tou-san, you're strong enough to protect our people. I want to be on your squad." Having had time to think it through, having seen how close to the edge his father is, Kakashi says more than he means to, but he knows his father won't doubt his veracity.
After the war, Amaya still isn't a Kunoichi- will never be, for all she was born for Kakashi, her parents are devastated when her beloved Aniki dies in the hospital, and Fugaku-sama himself says they've given enough- Sakumo retires to spend more time with Kakashi and the dogs, Kakashi reduces his missions to spend time with his Tousan and cherished best friend. He introduces Sakumo, whom they've met informally- on a bloody battlefield, the White Fang's squad hurrying to catch up to their Taichou when he realizes the squad they were sent to reinforce is Kakashi's, and the silver haired Taichou is in time to see some Iwa nin bloody his puppy. The Iwa nin dies screaming when a white, chakra imbued Tanto rips a second mouth in his gut- so that he can later introduce Amaya and be absolutely sure she has a protector even from his friends. Sakumo knows his son has chosen his mate. When Kakashi returns from a hectic mission to find his father with Amaya dozing in his lap, he splits from his team to call
"Tou-san? What's wrong with Amaya-chan?" Every ninja in hearing distance turned to see the Next White Fang stride to where his father sat in the shade, Amaya Uchiha curled like a cat in the man's lap. Rin, Minato, and Obito curiously came over to see this person that Kakashi called "-chan." Amaya opened whiskey eyes to blink sleepily at Kakashi and lifted her arms like a child demanding a cuddle.
"You're back, shitawashi." Hoisting her with the ease of practice, Kakashi replied
"Maa, maa, just routine stuff, my precious Amaya-chan," Turning to his sire, the boy added
"Arigato, Tou-san, she likes the sun too much." Sniffing at his disapproval, Amaya slid down, straightening her kimono to huff
"Shall we have your team to dinner, or will we eat at a restaurant, Kakashi?" Despite being not quite eleven, her reproach sounded distinctly wifely. Which is why Kakashi rejoined
"We're eating at Ichiraku with Kushina-san, Kami-san." Wrinkling her nose desultorily, Amaya activated a Shunshin and hurried away. Chuckling, Sakumo waved and used his own Shunshin. Kakashi sighed and said uneasily
"Six o'clock, I think." Before leaping after his family.
At Ichiraku, there were a fair few more customers than usual. Everyone wanted to know who Kakashi's girlfriend was. They were not expecting Akita Uchiha and her genin teammate Hizashi Hyuuga, Aishiteru and her husband Katon, and Biwako Sarutobi with her husband Hiruzen to show up. Or for Kakashi to escort a tiny, brown haired girl in a rose yukata with the solemnity of a Guardian Shinobi into the premises. Sakumo bringing up the rear was unsurprising, and not as unwelcome as it might have been, once. Tiny, and slightly pudgy up close, Amaya politely ordered a miso ramen and ate casually, listening to Biwako's story about an Uchiha who had passed away decades ago.
Although Team Minato, including Kushina, was a little hurt about not knowing her, Amaya calmly explained that she had been sheltered from the violence of the Shinobi world because they had given enough. Kakashi tersely explained his edicts about her movements. Biwako, Aishiteru and Akita snorted in unison.
"If you know anything about Hatake's, they're rabidly protective of their mates." Akita pointed out. Sakumo interjected
"Those we get to choose, Akita." Kakashi nodded.
"Tousan and Kaasan were an arranged match." Amaya heaved a sigh and declared
"I'm ready for bed unless we're doing something more cheerful." Kakashi took that as his cue, paying the bill and sweeping her out the door. Sakumo chuckled and quickened his own strides.
Later that summer, Amaya received a strange later from a place called Hogwarts. She and Kakashi wrote often as possible, Sakumo corresponding when his son was busy. Amaya came home every spare minute, but her family was ultimately grateful she got the chance to develop her own identity. In the summer of her sixth year, Amaya married a then seventeen year old Kakashi. The Yondaime had sacrificed his life, as had many others- but due to Katon and Aishiteru's intervention that night had spared Biwako. Once the Kyuubi events had settled, Kakashi forcefully made his case to investigate why his wife had not answered his letters in three weeks. What he found enraged Kakashi, but he reluctantly agreed to return to Konoha, where Faith and Honor needed raising.
When she finally came home, Amaya had lost her sister, many friends, and her parents since receiving her letter. She had, in the same time frame, gained a husband, two wards, a father in law and a daughter.
Obito goes missing three days after his eighteenth birthday. They discover he has been branded with a permanent control seal, and stolen Amaya and Kakashi's DNA samples from the District, a renegade doctor eventually producing a viable offspring whose growth had been accelerated to age sixteen in two years, information dumped on her until Obito fights the compulsions enough to send her home to the parents she knew about only because he stole every possible moment to tell her. When she is physically eighteen, the child who named herself Aishiteru for the grandmother her Oji-san knew briefly, escapes at Obito's bidding, putting her parents in an awkward place. It is Tenzou Yamato, oddly enough, who helps them. After befriending the strange Kunoichi-born Hatake, he is unafraid to take her parents to task and make them understand.
That in mind, the child of a pregnancy that they spent a difficult year concealing from the Hogwarts population, Akashina, quickly accepts her neechan, but also quickly accepts an offer from a distant relative in Sunagakure, a friend of a man who'd been named Yashamaru, the woman wants to focus on something good. Years later, all Konoha thanked God for Akashina.