Clan Symbol:

The clan was formed during the formation of the great nations. The keke gen kai of the clan is the ability to use the elemental dragons/demons in their swords. Back in the clans first years the elders sealed elements into their blades, but soon they found the ability to seal their compainions (the dragons) into their blades. The dragons were being hunted anyway, by the new shinobi of the land, for their scales and power that could be taken from their corpses.
A memeber of the clan can harness as many elemental blades as their body can hold, because using the keke gen kai requires great mental and physical strength, unless the person is the first born of the head clan member, then they inherit that strength from their parents. EVERY clan member, at the age of 10, is tatooed with the clan symbol somewhere on their body, most get it on their neck where it can easily be concealed from enemies. But it can be placed anywhere on their body; arm, wrist, face, etc.
The clan itself was broken down into different branches and set in different villages, currently there is one in the star village, one in Mist, one begginning in Leaf and the main branch is in Grass.
Each branch has it's own set of rules and ways of training, the main branch have strict rules and a harder training than the other branches. Also the seperate branches have their own set of jutsus that they have developed.
The Star branch has developed their keke gen kai to the point that they can read other people's thoughts by using the dragon's ability to. They can also communicate better with their dragon souls in the blades. Unfortunately each member can only harness so many elemental blades because of that.
The Mist branch has developed a way to completely harness the power of the dragons in their blades. They can even exchange their body for the dragons for a short time, becoming the dragon itself. But they also summon the dragon's concience, making it very dangerous with two minds in one body. Also they can only have one blade, and one dragon soul, because they can only bond with one soul. The clan members, once they have called upon the dragons soul will permently have that dragon's concience in their mind.
The Leaf branch is still developing new jutsus and ways to harness the dragons power.
The main Branch shares some of each seperate branch but on a smaller level. They do have the ability to learn the jutsu's but it would take longer for them to learn them. A head clan member, meaning their children as well, each develop a unique ability that no other clan member has. Although other clan members can on occassion develope their own traits, the head memebers are known for their emense power and abilities.