The change of a single line (Can't defeat Her, so instead I'll have to be Her) sorta warps my perspective on the song.

My reinterpretation, staying in line with how Shiva is in-game, leads me to believe that Shiva (and by extension Iceheart?) believe that death/oblivion is the only salvation/end to the War and have taken it upon themselves to become the new Reaper.