The Tetsumaki clan is native to Kumogakure no Sato and traits of their blood can be found here and there throughout Kaminari no kuni. The clan have an afinity for Raiton which is directly related to their hijutsu, Kami no Bodi Kaminari, or Divine Lightning Body.
The storm is the eclipse of a Tetsumaki's life. Seen as the staunch defenders of Kumogakure, they have always been relied upon for a force of strength and resilience alongside their cunning and speed.
From a young age the children of the Tetsumaki clan are trained to hoe their natural chakra affinity, raiton. Almost all members of the Tetsumaki Clan grow to become full fledged Shinobi and often find themselves in areas of power within the Village. Those who are born without the will to use the hijutsu, or do not have raiton as a natural affinity tend to be left on the sidelines as they are deemed unfit for training within the clan hierarchy.
The only higher loyalty the Tetsumaki hold besides their Village is themselves. A close knit community where only the strong survive the 'storm', the mastering of raiton control one might think they are shrewd and secretive. Upon entering their ranks or gaining insight into the Clan, Tetsumaki individuals are fierce defenders, passionate lovers and stubborn to the last and will quite often fight to the death for their clan or village.
Though not the oldest, the Tetsumaki have traces of ancestry back to the forming of Kumogakure. Initially seen as a religious sect in the mountainous regions of Kaminari No Kuni, they would eventually assimilate into the second generation of the founding of Kumogakure. But not before rumors of their founding as a Clan being seen as ones who conversed with the sky. Of course, as a religious cult, the first of the Testumaki believed the gift of the storm came from the Gods. Untrained and sloppy, the Clan was little more than a barbaric tribe with an uncanny ability to transform themselves into lightning.
Over the next few generations the Tetsumaki would become integral into the founding of the Village. Never seen in historical lore of recorded Kumogakure the Tetsumaki Clan was always the force behind the Kage, secretive and shrewd the Clan would never allow themselves to be seen in the limelight while other Clans basked in the glory.
A great deal of the Tesumaki died during the First Shinobi War, they fought to the death to protect their Kage, Mageruhi Raiden. When the first Kage fell, the Testumaki, enraged, continued to fight. The remaining few Tetsumaki would encourage their youngers to seek glory through battle and many remained loyal to the new Nidaime Raikage, Jokyu Otoshi, following him to the end of the First Shinobi War.
Not all Tetsumaki had died, and many lived to fall in the Second Shinobi War. Those who had been young in the first war had barely a chance to mature before the second war broke out. Battle-hardened veterans were first on the line to protect the Third Raikage and many fell in the first wave of the war. But thanks to the insight of the third Raikage, the war ended prematurely with only the younger of the Tetsumaki survivng and becoming angry at losing their chance to bring glory to their Clan.
Hana Testumaki was one of the first noted leaders of the young generation Tetsumaki, strong willed and stubborn to the last, the woman was a fearsome sight on the battlefield. Only a few years before the outbreak of the war Hana gave birth to a young girl, one of the newest members of the Testumaki. Borne to a man who had married into the Clan, the young child was the new hope the Clan had been looking for to revive the Tetsumaki.
The last battalion of the Tetsumaki warred, and died, on the skirmishes of the Third Shinobi War. Hana Tetsumaki had been killed in an ambush near the Sunagakure border after an arms deal had gone wrong. Nearly the entire battalion had been caught in an explosive blast that took the lightning Clan by complete surprise.
With only the small child left alone with her half-blooded Tetsumaki father it is still thought today that the Tetsumaki are all but extinct. One hope lies within a pink haired kunoichi who has only recently mastered the storm in her 27 years of life. With no younger siblings or surviving Clan members to speak of, the entire fate of the Clan is left up to the woman.
It is not impossible that a few members have lost their path along the way to the Tetsumaki. Indeed, there could be a chance for a Tetsumaki to crop up in a relatively small family of Kumogakure. Since not all children of the Tetsumaki could master the storm, many fell into city worker jobs rather than following the path of the Shinobi. Perhaps somewhere in the high mountainous region of Kaminari no Kuni there are still those yet to discover their legacy.
The Tetsumaki Clan initially had one linear hierarchy. The top layer was the Clan Head, usually the strongest of the Tetsumaki who ruled over all and concerned themselves with the directions of the Clan. Next would come the trio of advisors who were among the oldest and wisest of the Clan, they would advise the leader but would have no say in decisions made. The Clan Heir would come next, a child prodigy able to master the storm from a young age and deemed strong enough to master the art of the Tetsumaki Hijutsu.
Kami No Bodi Kaminari
神のボディ雷 [Divine Lightning Body], this is the name of the hijutsu which is thought to be more or less lost by most.
Rumored to have come from the Gods, or more simply, through generations of training, The Tetsumaki can quite literally manipulate lightning through their whole body. Becoming accessible from a young age (~4/5 y.o), it is the essence of what it means to be a Tetsumaki. Garnering the power to turn part or all of their body into lightning there is quite simply minimal limitation to the full mastering of what the Tetsumaki call 'The Storm.'
Kami no Bodi Kaminari renders the user unable to learn any other element, (though they still can use non-elemental jutsu) they are quite literally devoted to The Storm. But this enables them to use raiton jutsu as easy as one breathes, gives them the ability to travel through conductive elements such as water and earth in their lightning form and if used masterfully enough, can avoid most attacks with their profane speed. Quite literally, the Tetsumaki becomes The Storm that their ancestors once revered.
Of course all strengths have a weakness, the Tetsumaki who becomes devoted to The Storm cannot use any other ninjutsu element but raiton, naturally that has its own drawbacks. Mokuton users also have some advantage over the Tetsumaki since wood is naturally resilient to lightning. The other weakness is that the body being in the form of energy rather than a physical form allows Fuuton to vibrate and further separate the energy of the user. This at the very least will immediately expel them from their Storm Form, if not completely subdue them.