Countless ordinary people perished in the chaos of war.
Tips
culture
黄泉 (Yellow Springs) is the traditional Chinese underworld - the destination of the dead. The image comes from the belief that a yellow underground stream flows beneath the earth. Compare English 'meeting one's maker.'
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Literary and somber. Use for serious narration, historical writing, or eulogies - not casual conversation about someone passing away (use 去世 or 走了 instead).