Prologue: It was meant to bring peace…

Sengoku Jidai. A time of sweeping change, ferocious warlords…and unyielding violence. For almost two centuries, the nation of Japan was caught within the intense turmoil amongst the many powerful clans throughout the country; some rose to great heights, while others were massacred. Near the end of this period, after the death of the powerful Oda Nobunaga, Toyotomi Hideyoshi ascended to claim his late liege lord's many lands and continue his mission of unifying the nation. Allied to him was the Tachibana clan, a family of assassins and medical geniuses renowned for their abilities in stealth, medicine and poisons. All throughout Hideyoshi's rule, from 1587 to 1598, the Tachibana acted as the guardians and protectors of the Toyotomi clan and enjoyed fame and accolades the likes of which few would ever know. They were also greatly feared due to the participation of a number of more prominent Tachibana clan members in the infamous crucifixion of the twenty-six Christians: an act that would forever associate the Tachibana with relentless bloodshed and cruelty.

Eventually, the Toyotomi fell from power after Hideyoshi's failed attempts to invade Korea and China left his clan and loyal supporters with severely depleted funds and an exhausted military. After his death in 1598, the Toyotomi clan leadership passed to Hideyoshi's son, Hideyori. However, Hideyoshi's Council of Five Elders began arguing amongst themselves regarding who had a claim to more power. The Tachibana, who were charged with Hideyori's care, did their best to continue safeguarding the young heir during this uprising. Ieyasu Tokugawa, one of the five elders, eventually emerged as a powerful threat to the Toyotomi's continued rule. Allied under him were several powerful clans, including the vaunted Urashima clan, and the infantile Mononobe clan, a branch of the Urashima. The Urashima were well known in the political circles of feudal Japan for many years, and the Mononobe were said to be powerful warriors known for their talent at forging top-quality weapons and god-like swordsmanship abilities.

Throughout the conflict, the Tachibana and Mononobe fought many battles in the name of their liege lords. The rivalry developed between the two clans was fierce, and as Ieyasu claimed more and more victories the Tachibana grew ever more desperate to destroy the Mononobe, who were the backbone of Ieyasu's forces. The bloody time period came to a head on 16 October, 1600 at the Battle of Sekigahara. Refusing to acknowledge the true abilities of their rivals, the Tachibana stormed the battlefield completely assured of their victory. Their cockiness would be their undoing, as the Mononobe's fighting strength and tactical expertise gave them the advantage they needed to crush the numerically superior Tachibana. Tokugawa's victory at Sekigahara paved the way for his shogunate, and upon consolidating his power he rewarded the Mononobe by bestowing them with the appointment of Guardians of the Shogunate, a position previously held by the Tachibana under the Toyotomi's rule. The Urashima clan were also rewarded by becoming Tokugawa's political councilors. While the Tokugawa shogunate, also known as the Edo Period, was a time of peace, behind the scenes a war still raged. Infuriated by their fall from grace, the Tachibana began a blood feud with the Mononobe that endured for centuries. The Urashima clan tried to act as mediatiors, however the hatred of the Tachibana rendered all attempts at making peace useless.

It was not until the end of the Edo period that the feuding clans were forced to place their personal war on hold. In the 1860s, the Urashima clan observed the declining state of the shogunate and slowly began distancing themselves from the Tokugawa clan. By the beginning of the Boshin War, the Urashima were an entity of significant political prestige and power, and upon bringing the Mononobe back into their fold they were able to cut all ties between themselves and the Tokugawa. When war broke out, the Urashima accomplished the impossible: they brokered an extremely flimsy, unstable truce between the Mononobe and Tachibana in order to have them work together on the side of those who wished to restore power to the imperial court. Both clans forwarded their best warriors, assassins, forgers, and medicine makers to serve the imperial cause. By the end of the war in 1869, the Tachibana and Mononobe clans had earned many accolades, but with the imperial court victorious and Emperor Meiji restored to power, tensions skyrocketed between the old enemies once again and many feared that the ancient blood feud would be rekindled.

Having been impressed by the cunning nature of the Tachibana and the legendary skill of the Mononobe, Emperor Meiji came up with a solution to the danger of a revived shadow war: On 14 November, 1870 he wrote a decree for an Imperial Tournament be held between the two clans, with the Urashima and another prominent clan, the Aoyama, acting alongside the Emperor himself as judges. The two clans would put forth their best swordsmen who would compete in tournament style battle. The clan with the most victors would be given the honor of the title "Imperial Guardians" for the next 10 years. The emperor then had the current head of the Urashima, Mononobe, Aoyama, and Tachibana clans sign their names on the document in blood before declaring the decree to be everlasting until the end of time by placing not only his imperial seal, but his own signature in blood.

The signing of the decree became known as the unofficial end to the blood feud that had plagued the Mononobe and Tachibana clans for centuries since the Sengoku, and for decades the Decennial Tournament became a beloved tradition of the imperial court. However, despite outward appearances not all was well between the two clans at all…for old wounds seldom fade, and bad blood feuds die hard…