The Jaredite story is moving rapidly to the end. As it does, it continues to give only an outline of the facts, without filling out too many details. For example, verse 9 introduces Seth, but without telling us who Seth is, nor why he was brought into captivity. We learn that he is the son of Shiblom only in the genealogy (see Ether 1:11). As the son, and presumably the last-born son, Seth was to be the heir to the kingdom, but he was kept in captivity. In the end, Seth’s son, Ahah, succeeds in rebellion and gains the throne.
As the story moves to the final destruction, we see Ahah doing “all manner of iniquity in his days,” and his son, Ethem, “also did do that which was wicked in his days.” The continued iniquity will invoke the cursing part of the covenant of the land. Ethem is Ether’s great-grandfather.