The story of the Jaredites is a story of a specific lineage of rulers. Those who rule cities or areas who are not part of that direct line do not show up on the king list in Ether 1, even though in the text of Ether 9-10, that provides the chronological history of those kings, other names are mentioned.
The context for Shez is that he is the son of Heth (according to the king list), but here, in verse 1, he is listed only as “a descendant of Heth”). Heth was an unrighteous king, and a great drought occurred during his reign, a drought that was severe enough that it resulted in his death. Shez takes up the throne, and “did build up a righteous kingdom.”
Nevertheless, in the common Jaredite pattern, his oldest son (also named Shez) rebels against him. Lest we think that all of these stories are only type scenes, Shez, the son, doesn’t gain victory, and isn’t even defeated in battle. He “was smitten by the hand of a robber.” Mormon’s use of the term “robber” would have suggested Gadianton robbers, but while we see secret combinations in Ether, we do not see Gadiantons. Thus, “robber” really could simply be a robber. However, the possibility that it relates to a secret combination cannot be dismissed, as that is the leitmotif of the Jaredite record. When we see later, in verse 33: “And in the days of Com there began to be robbers in the land; and they adopted the old plans”, it increases the plausibility that the robber in verse 3 was connected to a secret combination.