Naruto: Hyuuga Uchiha Child
According to the creator of Naruto, if a Hyuuga and an Uchiha had a kid, the kid would have the dojutsu of both clans, one in each eye. This would be an interesting story to explore, especially since faking one’s death in the Naruto universe is definitely not impossible when one has Ninja-grade disguise and misdirection skills in combination with high-grade genjutsu via Sharingan; the only thing you’d have to look out for would be other people with Ninja-grade disguise and misdirection detection skills, of course, but staying in small civilian villages away from Hidden Villages, strategic points of interest, and high trade or highly travelled areas could leave someone pretty invisible as long as they don’t go blowing up half the country-side while they train.
So, picture this. Two women are rivals from different clans since their academy days. They graduated at the same time, got promoted at the same time, entered Anbu at the same time, got married at the same time, and had kids about the same time. Everything was a not-so-friendly competition, but these high-born ladies won’t admit to anything. They meet up every week at a small playground so that their kids can socialize with other clan children their age (and so they can subtly not-so-subtly brag about their kids’ skill levels or about clan success). So, while these two lovely ladies are passive-aggressively complementing each other in the most insulting ways possible without being outright hostile, their kids are becoming pretty good friends right under their noses. Once they’re old enough to walk around on their own, they regularly meet up to play and explore different areas of Konoha.
Eventually, their respective clans get involved and start warning them away from each other and they drift apart. Later on, when they enter into the academy, they’re almost as competitive as their mothers and more direct about their dislike. But they still remember being friends.
Eventually, Baby Uchiha gets fed up with everything and decides to be rebellious. They invite Baby Hyuuga to a public training ground for a spar. Baby Hyuuga wins the first round because Gentle Fist. Baby Uchiha demands a rematch and wins (keep in mind, their taijutsu is not very practiced for all that they’ve learned. They’re still kids without their respective dojutsu and growth spurts definitely don’t help with becoming familiar with their own bodies and fighting forms). The point is, they learn to respect each other and enjoy each other’s company again.
The Hyuuga activates their dojutsu first. Maybe they’re ambushed during one of their training trips by spying Ninja from another village that think it’ll be easy to nab two clan kids. Whatever is going on, Hyuuga pulls something like a Sasuke on the bridge in Wave and little Uchiha activates their Sharingan for the first time before help arrives. They grow a bit closer after that.
Through circumstances beyond their control - missions, sudden sickness, random accidents, maybe even clan-enacted justice for committed crimes - both kids lose or are separated from their direct family members. Their clans are also aware of their regular meet-ups and express their disapproval in tense group dinners and midnight ‘you’d best think about where your loyalties lie’ talks in the hallways of their compounds. The kids get sick of it, constantly talking with one another about how their clans care about nothing but clan politics and preserving their reputations. The bonds that both hold with members the village are either gone or incredibly weak. Except with each other. At this point, I assume that they’ve graduated the academy and have been on their respective teams for a while now.
Funny enough, in a reversal of the whole dynamic of the Uchiha as the instigator (like how they forced the circumstances needed to rekindle their friendship), Baby Hyuuga convinces their friend to leave with them. They bide their time and end up finding a way to manufacture the idea in the perfect peoples’ heads that their two teams should take a mission together in a town regularly visited by many Hidden Village Ninja from all over. They play traitor, anonymously organizing an ambush on their group (Their clans are well off. Did they save their pay from many different C and D-rank missions? Did they use family funds? Did they forge grand bounties for their Jonin Sensei? Something along those lines). The important end result of their meddling is a convincing double-death, where the Uchiha and Hyuuga fight back-to back before the Uchiha lights up the surrounding area with a Fireball Jutsu hot enough to turn flesh to ash and violent enough to scatter remains. The kids, a bit burned, disappear without being seen - except maybe by one of the missing nin that showed up to watch the fight, who finds the whole situation funny and doesn’t plan to interfere in any way - and they’re considered KIA.
Now free from their village, Ex-Hyuuga and Ex-Uchiha settle in an out-of-the-way hamlet in Whirlpool country, because they know that ninja from Konoha usually avoid the area because the destruction of Uzushio is still a fresh wound for all that it’s several years in the past. They are careful and paranoid because they’ve been raised on stories of missing nin being heroically hunted down and on dastardly things other villages have done in an attempt to get their hands on the Byakugan and Sharingan.
But they’re free. They sometimes fight, and they stumble their way through clan techniques they haven’t quite mastered and can’t really help each other with. They miss having the protection of more than just a small group of civilians, sure, but they’re not eager to return to that sort of life. They have a few close-calls with enemy ninja, especially after the Third Shinobi War picks up, but they live in relative peace.
They become traders for a time, and one of them becomes very proficient in Herbology. They go around selling medical concoctions to all and poisons to those who know to ask for it.
Then they have a child of their own, who they raise to be just as medically and financially savvy.
The kid is street-smart, and they manage to activate their dojutsu fairly early, but not early enough to be labeled a prodigy like Itatchi was. Their parents’ clan training was hindered by their leaving the village, but they teach the kid what they can and they end up developing a strange mix of Uchiha and Hyuuga fighting styles that wouldn’t work with anyone but them ( anyone without the near-omniscient pattern recognition capabilities of the Sharingan and the precision and all-seeing nature of the Byakugan). The Hyuuchiha learns what it means to fight for survival and that there is no honor or pride worth keeping on the battlefield; dirty tactics are acceptable always when your life or your way of life is at stake.
The kid is an absolute demon on the battlefield. There is nothing they won’t resort to in a fight. I like the idea of them being a bit demure in personality, quiet and reserved, but 100% willing to interact and bargain with a potential customer while smiling sweetly. That is, until someone makes them angry. Then, it’s all glaring Uchiha whose ‘god-is-dead’ customer service smile could crack glass.
Obviously, I haven’t really considered most details. The Caged Bird Seal is a problem that needs to be addressed unless the Hyuuga parent was a part of the Main Family. That could also be one of the reasons Hyuuga convinced Uchiha to leave the village; maybe the loss of their direct family members put them in the care of the Branch Family and the elders were planning on having them marked. Someone is also technically an adult once they reach Genin, though, so I’m not sure if that would work. And how would they interact at all with the canon characters of Naruto and Naruto: Shippuden? Are they simply a background character that bares witness to a few shenanigans here and there, one that anonymously solves a problem or two for the main characters before they have a chance to deal with it but otherwise has no real importance? Or are they dragged into the main storyline and have a direct impact on the events of the series?
Take my idea. Make it yours. Have fun.