Clan Saiyuki
A clan that has always had full-demon blood but never had any connection to the Bijuu, due to their nature of being secretive and hating to hurt their fellow citizens of wherever they live. Because they don't want to hurt their friends, they hide their demon natures with things called "Power Limiters" that are designed to limit a demon's power and make them more human in appearance and style (as well as personality). They really hate to hurt the humans they live with, so they decided to make some clan rules to stop the hurting that they might cause friends, such as:
1. Don't take off your Power Limiter(s) unless it's absolutely necessary, and if you do, only for a limited time of half a day at max. You don't want people to kill you for what your born as, now, do you?
2. Only fight when you can't avoid it, when someone challenges you, or you are on a mission that involves thugs or ninja that don't know your code of honor.
3. Fighting amongst each other is highly frowned upon, unless it's to spar with each other, in which case you are only allowed to fight with training restraints on to prove that you are willing to keep from killing each other.
4. Never fight over what you are supposed to eat. The grown-ups are the only ones who get to eat 50 pounds of meat per meal, and being a grown-up is when you live to be 55 years old or older, which is still young compared to humans. Sages get less meat, because they prefer sage fruit, unless they specify otherwise.
Yeah, they have some weird rules that wouldn't make sense to the people visiting the clan, but it's normal for the people of the clan to live with such restrictions... and that was only less than 1% of the rules (they have 1,000 rules for the way their supposed to live). They have special jutsu's depending on what branch of the clan they fall under:
Kappa: Water-based turtle-demons that represent green humans with a water bowl in their head full of water (the legend of them being immobile when that gets empty is a false story... a Nara ended up using Kage Mane to trap a Kappa when it was trying to get the excess water out of it's bowl head and had it emptied when a fight was going on, and a passerby saw the Kappa when it's water was gone, saw that it didn't move, and ran off to tell everyone else the weakness of the Kappa demon,... only the Kappa broke out of the Kage Mane to get free of what he unwittingly got stuck with. A Kappa's true weakness is the fact that you have to have it guess what element of jutsu you're going to use on it and have said guess wrong before you use the jutsu on it; that is the only way to kill a Kappa) and the torso of a Galapagos turtle. They are known to use the Demon Arts of Water Jutsu's, like Kappa Bubble, or Kappa Suiryuudan. When they have Power Limiters on, they don't look like their demon form except to have bald heads from a young age until they reach the human equivalent age of 50, or 500 in the terms of the clan.
Neko: Fire-based cat-demons that have tails, they're the only members of the clan that would get confused with the Bijuu, specifically Nibi (except that they have the ability to grow more tails and get more power than the Nibi). Not only do they have Fire Jutsu's in the Demon Arts (like Neko-bi Kai, or Soul Cat Fire, when translated), they also have Power Limiters that make them only have a weird bump out from the back side, with nothing else to signify that something's wrong with that person.
Tengu: Wind-and-lightning-based bird-demons that are known to be great sages from a young age, these demons are sub-classed into different categories, the riddler and the trickster. The riddler is signified by it's long nose, the trickster is signified with it's beak, and there are two types of Demon Arts that they follow (depending on the sub-class); Demon Wind Jutsu's for the riddler (like Wind Rake) and Demon Lightning Jutsu's for the trickster (like Devil Lightning). Their Power Limiters are designed to give them normal arms and have their bodies look more normal (especially their faces).
Inu: Earth-based dog demons that have tails but are also able to hide them while their Power Limiters can't (they use genjutsu to hide the tails and have it so that it can't be detected by anyone not born into the clan or married into the clan). They use Demon Arts in Wind and Earth Jutsu's, ironically speaking, because they learned how to manipulate wind chakra from an ancestor of long ago (*cough*InuYasha*cough*) and they able to use special jutsu's meant for the Inu, as well as the fact that they have Demon Arts in Earth Jutsu's (e.g. Wolf Doryuudan). Their Power Limiters were meant to hide their ears and their fur, but never the tail, due to their Genjutsu.
Each branch has it's own part of the bloodline that is different, like breathing underwater for the Kappa, walking on Lava for the Neko, levitation (intended for flying purposes) for the Tengu, and regeneration for the Inu. Each is supposed to be a good benefit to the world in one way or another.
That is what I have to say on the Saiyuki Clan... other than the fact that I know what "Saiyuki" means. I'm sorta basing this off of the anime Saiyuki. That is where I got the inspiration for this clan... and, no, there won't be a "Monkey King" in the clan.
