User blog comment:Rafe Adler/"Stuck in the Middle (With You)" Discussion/@comment-1031724-20170217183659/@comment-24834479-20170217190836

I think that the 5 things it can't kill are species rather than individual beings. Also it is stated that there are 5 things in all creation that it can't kill. I place God and the Darkness outside of creation so I think they don't really count. My best guess is Archangels, Leviathan, Horsemen, Knights of Hell (powered by darkness), and maybe Eve.