The word "sword" is used here to refer to a battle or war. AT: "will die in battle" or "will die in the war" (See: [[rc://en/ta/man/translate/figs-metonymy]])
Here "cities" represents the people of the cities. The abstract noun "captivity" can be expressed with the more concrete noun "captive" or the verb "capture" AT: "the people of their cities will become captives" or "their enemies will capture their people and take them away" (See: [[rc://en/ta/man/translate/figs-metonymy]])