The Last Dragon Of Konoha
The Iron Dragon is a shinobi clan that originated from Land of Iron, before the shinobi clan wars. They had been in constant war with the samurai of the Land of Iron, after decades of conflict the Iron Dragons were finally pushed out just as the clan wars had begun.
With their home lost and nothing to lose, they went south to join the war, they soon became famous for their physical and mental endurance, as well as their skill and knowledge in chakra control/manipulation.
Their most striking trait was the ability to form seals with one hand and the best of them could even use two jutsu at the same time. In the war with the samurai were they forced to specialize in defensive and body enhancing jutsu, something they shown with great mastery in the clan wars.
In their three centuries long existence only a few have shown to have a Kekkei Genkai, which they called "Metal Release." It is said to give the user the ability to generate metal out through the skin and control any metal they touch, bending it to their will.
Unlike "Steel Release," where the user could turn their skin into steel, "Metal Release" did not allow the user to turn any of their body parts into metal, but they could create any form of metal; spikes, plates or bars, the form did not matter. Since no cases have been documented, it resulted in the "Metal Release" to be considered a myth by many.
After a few years in the clan wars, the Iron Dragons join up with the Senju Clan, working as personal bodyguards for high profile personnel, creating a tradition where young Iron Dragons would be assigned from soon after birth to another high profile child around the same age, to protect and serve the child.
This resulted in them being very close to each other; not once have the Iron Dragons ever betrayed their responsibilities. Some years after Konoha had been founded, this tradition came into effect amongst all of the bigger clans; the Senju, the Uchiha, the Hyuga, the Aburame the Akimichi, the Yamanaka, the Nara, the Inuzuka, and the Uzumaki.
However, due to the clan's protective nature toward their lords, many of them sacrificed themselves. They held the enemy off while their master got a chance to escape, saving their lords but dying as a result. Due to this, their numbers began to decline, until there were almost none left. Many noble clans unfortunately considered them a weak and broken clan; those that had fought side by side or against them, respected them and saw them as an honorable clan, truly worthy of the name Iron Dragon.
The most famous example to their loyalty would be the brothers, Ichirou Tetsuryu and Jirou Tetsuryu. Ichirou, who was the older brother, was the guardian of the first Hokage, Hashirama Senju; the younger brother, Jirou, had later become the guardian of Madara Uchiha, the leader of the Uchiha Clan in Konoha. They both were a part of the battle in the Valley of the End, and were forced to fight each other.
Both brothers were killed that day; Jirou was the first to fall, as he perished at Madara's hand when he had been injured by Hashirama. Ichirou was gravely injured when he shielded Hashirama from the Kyubi's tailed beast ball. He succumbed to his wounds in the end.
Many others have been known to be accompanied by the Iron Dragon guards. The second Hokage, Tobirama Senju, the third Hokage, Hiruzen Sarutobi and his wife Biwako Sarutobi, the fifth Hokage, Tsunade Senju; former leader of the Uchiha, Fugaku Uchiha and his son Itachi Uchiha; the head of the Hyuga, Hiashi Hyuga and his daughter Hinata Hyuga. Her guardian is the last known alive to this day, who goes by the name of Isamu. He currently lives with Hiashi, since his father died and was the guardian of Hiashi. The Hyuga have taken care of him ever since his father died when Isamu was four.