Darkness stirs. Nobility rules. An empire starts to collapse. A rebellion rises. Bounty hunters reign the most.
It is a period of civil war, and one lone bounty hunter, Mukutachi, hunts in the shadows alone. Hated by all and respected by few, he is a lone ninja who made his living to kill monsters without honor, to defend humanity without honor.
During a mission, he is suddenly sucked into a tormented world he has no desire to be a part of. No matter how he keeps his distance, fate has brought him to to a world where a world needs warriors. But he is just one warrior, one man, one ninja. But one ninja may be the key to breaking a civil strife that has strike humanity and other mortal species for three hundred years.
And he is just the catalyst of a prelude of what is to come. A series of Uprisings, Civil Wars, and twelve Zodiac Warriors fight to the bitter death and only one victor may come out on top...