The lyric actually begins "Then we saw Mishima's Dog," not "mission is dark." Always best to check the artist's website to avoid misinterpretation.
Mishima's Dog is a direct reference to Yukio Mishima's noval "Spring Snow"--where a black dog becomes trapped in the rocks of a waterfall--an omen of things to come.
I would interpret the lyrics overall as that of a ronin--a samuri without a master ("I don't know who I am").
The lyric actually begins "Then we saw Mishima's Dog," not "mission is dark." Always best to check the artist's website to avoid misinterpretation.
Mishima's Dog is a direct reference to Yukio Mishima's noval "Spring Snow"--where a black dog becomes trapped in the rocks of a waterfall--an omen of things to come.
I would interpret the lyrics overall as that of a ronin--a samuri without a master ("I don't know who I am").