Since the beginning of time, monstrous Demons and noble Guardians have battled for Earth - the everlasting gift of the one great Mother, creator of all life. A deep hatred burns between Demon and Guardian; the Guardians prevented the Demons from destroying humanity and the world itself. Eons later, Neo-Shinjuku City: few Demons or Guardians remain to continue their epic war. Humans rule the Earth, with no real memory of either Demons or Guardians. Yet deep within the dark underworld of the city, one supreme Demon is alive and plotting to subjugate mankind. Only one Guardian is left to do battle, and the fate of the human race is at stake. Based on the Graphic Novel Twilight of the Dark Master (Shihaisha no Tasogare) (Shinshokan) by Saki Okuse (Source: DVD Back Cover)

In spite of their defeat, the remnant factions of the Taipingtao Revolution continue to resist, plunging China into a seemingly never-ending war. Moreover, the negative emotions left behind by the rebellion's massive death toll begin to form miasma—giving birth to malignant beings called the wangliang. These creatures can possess humans and turn them into horrifying demons, thus bringing about more deaths and miasma and spinning a vicious cycle that inflicts further despair upon the land. As a countermeasure, the immortal deities known as the Tianyuan select certain individuals to be Hunters. Accompanying them are the Guizhan, specialists created by the Tianyuan who can absorb miasma and transform into demons themselves, acting as indispensable weapons against the wangliang. After a tragic accident involving an out-of-control Guizhan causes the disbandment of the Sixth Hunter Unit, the Tianyuan designate three promising Hunters—namely Ji Ying, Qiao Xun, and Yan Ding—to reform the group. However, for an unknown reason, the Tianyuan also appoint Xiao Ling—the young Guizhan responsible for the former unit's downfall—to fight alongside the trio. Despite growing tensions, the members of the revived team must settle their differences and collectively use their abilities to attain victory against the common enemy.

In the year of Tenpo 14, Yoi, monsters from another world attack Edo. Those who fight against them are members of Bansha Aratemesho. In public, Bansha Aratemsho is known as an organization to study foreign books. In fact, they are a organization dedicated to destroying the Yoi. These warriors are called Ayakashi. They gather information of odd events in the country, and are sent to destroy Yoi who appear. They are generally very strange people. For example, a guy who has lost his memory, a girl who dresses like a man. They have special powers with which to beat the Yoi. (Source: AniDB)

The neighborhood cock of the walk is more than just an ordinary rooster—he's humanity's greatest defender! His opponents may be ten stories tall, but nothing is bigger than his stout heart and his fearsome battle cry—cock-a-doodle-doo! (Source: VIZ Media)