Their sixth album "Takasago Army" was released on Spinefarm Records in 2011. This album is based on the story of the Takasago Volunteers, Taiwanese aboriginal soldiers who fought for Japan during World War II. The album included guest appearances from singers Yu Tien and Chan Yawen, and Taroko musician Pitero Wukah on pgaku flute. Main songwriters Freddy Lim and Jesse Liu stated that "Takasago Army" marked a reversal in the band's writing, as the songs were first written in a traditional Taiwanese folk format but were then played with heavy metal techniques. Doris Yeh stated that the Western definition of "heavy metal," whether it is black metal or death metal, cannot easily define Chthonic's style; thus, having to choose a term, the band uses the term "Orient Metal."