What? You say His Majesty is a war criminal!!

“Neutron annihilation, earth-exploding stars, happy angels, Colossus annihilation, dimensionality reduction strike, black hole annihilation. Open your eyes and see how many races in the galaxy have been exterminated under the ambition of that tyrant!! The Holy Emperor is a very evil person! A humanist, an out-and-out war criminal??”
“What? You said His Majesty is a war criminal?? Oh my God, you damn heretic. Quick, call the fleet immediately to execute the extermination order. This planet needs divine purification.”
PS: Elements of this book: wasteland, mechanical prosthetics, out-of-control AI, genetic modification, extraordinary awakening, interstellar warfare, empire building, and the indescribable Cthulhu evil god and subspace demon.