Ether 15:29 states that "they had all fallen by the sword save it were Coriantumr and Shiz." Brother Hugh Nibley has written the following concerning this problem:
Two circumstances peculiar to Asiatic warfare explain why the phenomenon is by no means without parallel: (1) Since every war is strictly a personal contest between kings, the battle must continue until one of the kings falls or is taken. (2) And yet things are so arranged that the king must be the very last to fall, the whole army existing for the sole purpose of defending his person. . . . As long as the war went on, the king could not die, for whenever he did die, the war was over, no matter how strong his surviving forces. Even so, Shiz was willing to spare all of Coriantumr's subjects if he could only behead Coriantumr with his own sword. [Hugh Nibley, The World of the Jaredites, pp. 235-236]