This piece I did with no wind instruments or strings, just percussion and choir synths. I had originally intended for it to be a super-intimidating boss fight against a powerful demon, it turned out to be better set for a strange and threatening temple, probably filled with hordes of enemies (i.e. creepy cultists and dark priests and stuff in a game which had no previous enemies of that nature) and a trap here and there. The temple would definitely be hiding something, be it "an ancient evil sealed away for all time" or just a Macguffin.