OE

A “salvo” is a simultaneous release of bombs and is often used metaphorically to mean the start of some kind of fight; this is a better fit to describe the opening battle than either “finale” or “blissful.” Every clue in the sentence is negative, so you want to describe the battle’s conclusion in a negative way—only “sanguinary” (involving much bloodshed) matches. The other options, “celebrated” and “blithe” (untroubled happiness), are the opposite direction. Finally, a “stillness where there once had been streets and squares bustling with life” is neither “blissful” nor “routine,” but very much disturbing, or “disquieting.”