An anime based on the Romance of the Three Kingdoms novel.

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. [Written by MAL Rewrite]

The Imperial Seal has been passed down through the generations since ancient times. It confers great power unto the warriors that it chooses. This is the story of those warriors. It is a time of chaos and of civil war. It is a time when great armies clash in titanic battles and great heroes carve their names in history. It is also a time of death and destruction, when the people of the land live in constant fear of the sword. Onto this stage steps the reluctant Rikuson (Lu Xun), whose family had been the guardians of the Imperial Seal up until it was stolen by Sonsaku. At the behest of his mentor Rikuson offers his services to Sonsaku with the intention of confirming the will of the Imperial Seal. However, assassins strike down Sonsaku and the Imperial Seal is lost. So begins, Rikuson’s journey to recover the Imperial Seal and discover his destiny. (Source: AniDB)