The word “demented” – which means “raving mad”, has been included in the poem due to the raw image it presents to the reader. When one thinks of something demented they think picture someone truly who’s truly lost it/gone off the deep end. Their not just mad, their demented. It has been included to show the reader how broken the loved ones of these soldiers are, and how they will never be well again.
“monstrous anger of guns” which uses the language technique of personification, has been included in the text to convey to the reader the massive larger then life roar of these weapons when fired, and how they sound like the howls of a monster.