This is a very well-written, and actually, a painful piece to read....You have done a brilliant job of describing the vast suffering and sorrow of all sorts damnation.....
Personally, i believe in reincarnation....so "for infinity, for eternity" is too much for me ....but for the actual demons?...well, perhaps.....As we all know, real suffering Feels eternal....though I believe we continue to work on ourselves through many lifetimes.....In any case....an incredible,recognizable, and chilling write...
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Two details I offer for your consideration:....you have sunk (rather than sank)...and.....'melancholic'
melody.....I don't think melancholous is technically a word...creative try, though...