Muzen is an group of hired assassins lead by Zennosuke Otou. They will kill any target as long as they feel it serves justice. Tesshu Fujioka and the Jinnai brothers Sakyo and Ukyo are former members of Muzen. During the events of Wrath of Heaven Tesshu is given a final assignament by Zennosuke; he is tasked with exterminating the traitorious Jinnai brothers. Tesshu accepts and leaves, unaware that the assignament had been the final words of a mortally-injured Zennosuke.