One day, the Uzumaki clan will be legendary. They will be trademarked for their use minimal use of jutsu yet being able to achieve maximum results. Their use of the Kage Bushin, the Rasengan and the Hiraishin techniques will mark them out as the strongest clan of Konohagakure. They will be near limitless in terms of their chakra levels, physical endurance, and unpredictability in battle. Each generation will have more chakra than the last. And each generation will be more unpredictable and thus unstable than the last. Their instability will eventually reach a point where they are unable to utilize any jutsus, as the moment they begin to channel their chakra in any form it will trigger a berserker state. The skill, knowledge and strength of character of their sire, the first Uzumaki, will be lost; consigned to the ether as his clan becomes legendary for being nothing more than raging demons.
Eventually, the Sharingan of the Uchiha will achieve a third level, a level beyond the forbidden Mangenkyou. This new form of the Sharingan will be a combination of and will surpass the first two stages. It will be able to not only copy jutsus the Uchiha view, but will have the capability to steal all jutsu knowledge from the target's mind; even before they are able to use a single technique. The theft will be so complete, that the victim will be unable to recall how their own techniques work. This new level of the Sharingan will not only be able to trap a victim in a mental world that the user chooses, it will transport them there in the flesh. Only to be released at the discretion of the user. The fact that, once achieved, the user can never deactivate their Sharingan will not matter to the Uchiha. Nor will the fact that within five years of activating the third level, the mind and body of the user will be overloaded by their own bloodline.
As time goes by, the Haruno will never be able to keep up with the other shinobi clans of Konohagakure. Not in any physical sense at least. Realizing this, the clan dedicates themselves to knowledge. The average IQ of the clan will increase with each new birth. They will develop genetic traits relating to their extreme intellect; such as a photographic memory, and total recall of information. Eventually their knowledge base itself becomes genetic, being passed on from parent to child in such a way that each member is literally born knowing every facet of information their parents knew at the time of conception.
At some point, the shadow techniques of the Nara clan will have a physical impact on its members. It will begin with darker hair and skin tones, followed by a slight ocular sensitivity to light. This will be assumed to be a recessive gene and will be ignored by both the clan and the Konoha medics. When a member of the clan is suddenly born as an albino, followed by another, and another and another and still more beyond them, it will become a concern. But at this point it will be too late. The Nara will be permanently bound to the shadows. And much as shadows vanish in the light, the members of the clan will be burned, fall ill, and even die when touched by sunlight.
Similarly, the body expansion techniques of the Akimichi will have long term effects. Nothing quite so toxic, but far more prominent. Each child born into the clan will grow to be larger than their parents. While being six feet tall is not unusual, and eight feet tall being odd but not unbelievable, growing to ten feet tall will cement the Akimichi's shinobi role as physical combatants. At twenty feet tall their size will become a concern. And at fifty feet the village will have difficulty supporting a clan of giants. Being literally no longer able to fit into the village, the Akimichi will breed their last brethren.
The final clan of the Ino-Shika-Cho trios will fare somewhat better. The mental capabilities of the Yamanaka's will reach a point where they no longer need to use techniques to read minds or possess others. Before long, each member will possess natural telepathic abilities. Many will go beyond this and acquire empathic skills as well. Still more will become telekinetics, precognitives, and clairvoyants. They will eventually retire as shinobi, instead finding other ways to support Konoha with their skills.
With each generation, the Inuzuka will become uncannily more canine. Each child will have sharper teeth, stronger senses, even thicker hair. Their techniques will become more fluid, and their communication with their dogs more natural. While this occurs, the Inuzuka dogs will be growing steadily more human, their wits sharper and their language clearer. The clan's techniques will soon be lost as the humans can no longer perform them, and the dogs are unable to learn in time. Soon, the 'humans' will no longer be paired with the 'dogs' as children. Before long, the clan will become so feral that the rest of Konoha will be unable to see where the men end and the dogs begin.
Before long, the Aburames will be submerged by their Kikai allies. Ironically, this will be caused by the pursuit of tradition, and through attempts to perfect the bloodline of their clan. At one time, Aburame children had their first Kikai colony implanted at the age of twelve, when the child entered the Konohagakure shinobi academy. The tradition soon became such that the implantation occurred progressively earlier. At the age of ten, at age five, then once the child could walk, once they could crawl. Eventually the tradition dictated that the implantation occur at birth. Soon, the Kikai themselves will have enough influence that when an Aburame woman becomes pregnant, the Kikai of her colony will send a young queen to begin her colony inside the unborn fetus.
The Hyuuga insistence on purity will cause the ruin of their Byakugan. Their refusal to allow marriages outside their clan will cause a backlog, an overload of recessive genetics. While this will first create a boon as it causes members to be born with increasingly stronger Byakugan. Eyes that can see further and in more detail. Eyes that at one point even discover a more finite system within the existing chakra circulatory system. A discovery that causes the Jyuuken style to be completely refined to exploit this new system. There will be a price. An entire generation of Hyuuga will be born without the tell-tale pale eyes of their clan, eyes that are solid black instead of the Byakugan white. From this point onward only half of all Hyuugas will be born with white eyes. Of these, only half will possess the Byakugan, the rest will be born without eyesight at all.
The Rock clan will never be able to mold chakra and thus will never be capable of even the simplest of jutsu. This trait will actually increase in strength through the generations. Oddly enough this will prove to be an advantage to the clan. As their chakra becomes harder to manifest, it will also become more difficult for the chakra of another person to 'stick' to a member of the Rock clan. With minimal concentration, a shinobi of the Rock clan will be able to suppress their chakra completely, causing other jutsus to simply 'fall off' them. This will prove especially useful against genjutsu, techniques that operate by being applied to the victim's chakra. This odd trait, combined with their taijutsu mastery and knowledge of the chakra gates, will actually combine to one day make the Rock clan an effective clan of ninja.
The Long clan has never, and will never have a bloodline. They will never develop one, as their family tradition of weapon mastery will not have an effect on their genetics. Overshadowed by the other clans, a disgruntled Long clan shinobi will perform decades of research. Eventually, this member of the clan will perform a kinjutsu on the entirety of his clan. It will be labeled a kinjutsu, because it will massacre the majority of the Long clan. The only survivors will be rendered incapable of performing any shinobi skills for the remainder of their lives. However, the effects of the kinjutsu will arise in their children. The kinjutsu will cause all future members of the Long clan to merge with certain materials. Specifically, they will become able to merge with their weapons. Wooden staves and nunchaku. Steel swords, spears and shields. Iron clubs and kunai. Even paper explosive tags. The former weapon mastery of the Long clan will be subsumed by this trait. In one generation the clan will shift from weapon masters, from warriors; to simple weapons, walking armories for the remainder of their existence.
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This idea has been in my mind for a few weeks now. I got to thinking how the clans of the konoha genin crew might look in the future. Obviously, this only works if you ignore not only canon pairings for the characters, but fanon ones as well. It's the only way the clans stay pure enough to produce bloodlines.
Also, I first saw the idea for the Inuzuka bloodline in the story "Catch 22" by "The Sh33p", an excellent read, I simply took the bloodline a step further than he did. The other bloodline ideas are mine as far as I know. If other authors have used them, I haven't seen those stories. A final note, the Long clan is Tenten's family. I've seen Long as her surname in various fics and I've always liked the sound of it.
At any rate, I hope you liked this chapter. There will be one more after this. And as always, I look forward to hearing any comments, concerns, thoughts or criticisms.