Dragon Knights

Dragon Knights were a legendary order of samurai from centuries past. They were taught to empower both their body and mind with the strength and wisdom of the dragons, taught directly by the creatures themselves. Once hailed as the original daimyos, this order has since all but died out, leaving only one true Dragon Knight left and a group of samurai dedicated to keeping the memory alive.

Ancient Traditions

The First Dragon Knight

Very little is known of facts surrounding the first Dragon Knight, the actual records being lost in the annals of time. However, it is widely believed to be Hachiman, the kami of war, as his mythos tells of striking a deal with an Ancient Edict Dragon. With his greatbow, Tengoku-no-Shikaku, he and this dragon quelled a calamitous force. With the blessing, acknowledgement, and strength of the Edict Dragon, it declared him worthy of being a kami.

The Old Ways

Fortunately, scriptures of the old ways still exist in temples to Hachiman across Hirashi Island. Protected by Tatsuo's respect of Hachiman, these scriptures have made their way into literary texts and is a focal point for Rekishi, Keihatsu's division of historical studies.
These texts detail the ritualistic process of honing one's body and mind under the tutelage of the dragons of yore. When a samurai, pure of soul, were to approach one of the temples designated to the Dragon Knights, they would train their bodies in preparation for being chosen. If they were deemed worthy, a young dragon would claim them, binding their souls together until the samurai strayed from the path.
After being soul-bound, the dragon would stay with the samurai through day and night, allowing its aura to mingle with the warrior's. During this process, the samurai's body would change due to this proximity, becoming one of body and mind with the dragon. Simultaneously, they would listen and learn to the dragon's counsel, its wisdom that was passed down from its forefathers now being passed down to the samurai.
Under the dragon's jurisdiction, one day it would deem the samurai worthy of the title "Dragon Knight". In doing so, it would willingly give up part of its blood to fuse with the samurai, infusing them with the blood of dragons. This process, though excruciatingly painful, marked the end of the preparatory stage of the Dragon Knight. For the rest of their life until their death, they would enter the "learning" stage, in which the wisdom of experience and time would be their teachers.

The First Lords

Eventually, chaos would return. The myths and legends tell of Hachiman and the 4 Legendary Dragon Knights working together, deciding that order would have to be made and maintained in order for the continent to thrive. Together with their dragons, they carved out the five islands that make up the Isles of Hisari today, giving one of the islands to each of them. 
To Tomoe, first son of Hachiman, the West. The storms and snow made for comfort for the Archer of the Storm.
To Tadakatsu, second son of Hachiman, the East. The copius amounts of metal and volcanos made for fuel for the greatest tactician of the four.
To Musashi, third son of Hachiman, the North. The vistas of forest and mountain made for beautiful backdrops for the arts which thrived under his tutelage.
And finally, to Yamato, fourth son of Hachiman, the South. The separate islands made for a playground for the swiftest of samurai.
In splitting the islands, the dark center was formed, the heart of corruption and entropy which held the continent shackled. Hachiman, kami of War, decided to oversee this darkness to prevent it from reaching his sons. In doing so, he would act as a bulwark, allowing the four islands to thrive under his watchful gaze. And thus, God-Emperor Hachiman and the first Daimyos were founded.

An Order Broken

While the scriptures which detailed the process of becoming a Dragon Knight survived, not all of history did. All historians have been able to piece together so far is there was a falling out between the Dragon Knights and the Dragons, causing them to make the final decision to no longer train the soldiers of men. However, the traditions are not so easily forgotten, and have become a new art passed down from samurai to samurai. When the old ways no longer hold sway, new traditions are born, and in deference to their roots, have changed their name into a new order: Sword Saints.

The Four Paths

No longer being able to go to dragons for their blessings, the samurai turned to the masters of old. Despite never being able to reach the heights of those legends, four paths of Sword Saints were born, each following the path of one of these legends. The Path of Tomoe, the Path of Musashi, the Path of Tadakatsu, and the Path of Yamato. 
Each of these paths were once taught by true Dragon Knights centuries ago. However, in current times, all of the Dragon Knights but one have long since died out. As such, the Sword Saints now teach those they deem worthy: samurai as pure of spirit as their predecessors. These Paths are no longer a formal training in any set location; rather, they are taught by wandering Sword Saints themselves.
A Sword Saint is never idle, always vigilant, and most importantly: always learning. They make it their purpose in life to keep the knowledge of tradition alive, and to teach future generations to never forget the past which birthed the art of honorable and graceful combat. In times of dire need, a Sword Saint can always be relied upon to come to the aid of the defenseless.