Even though Kib was effectively in prison, that did not mean that he did not have access to his wife (or wives, more likely). Thus, in his old age he has another son. Importantly, that son is not restricted to a prison, but is free to raise and arm a rebellion that successfully defeats his older brother Corihor. This releases Kib, but Kib is not restored to kingship. That passes directly to Shule.
Verse 9 speaks of creating “swords out of steel.” There is no known metal forging that early in the New World. This may be a translation issue. The brother of Jared had “molten” stones, and perhaps that term is used for stones here. If so, it would have been obsidian which was the standard means of providing a cutting blade in Central America, being much sharper than knapped stone. Some obsidian can be knapped to be as sharp as a surgical scalpel.