As long as you backrow Shiva for either Belphegor or Triton, you shouldn't be having any issues with the holy trinity on your side.
Belphegor will basically let you skip Rage phases (her first skill is ridiculously good), and Triton's combo- keeps you safe from multi-hit attacks, meaning that bad luck of losing some random Hime is far, far less likely. It can still happen if a boss decides to attack a specific person in your party turn after turn after turn after turn after turn, though.