I really wouldn't worry about detail in the summary. You just need the essence of what happened and leave the actual story to fill in the detail:Ah, right, I meant to answer that as well. The Olympians cursed them multiple times in retaliation for staying behind. Hephestus made 100 swords actually capable of killing the Godline and handed them out just before he left. Then Ares left a strife curse that made all of them more prone to violence. (Those curses did get resolved when one of the rulers sacrificed himself to destroy the swords). But almost immediately after that (ten years), Hera got mad at how the latest ruler was ignoring the prophecies (basically the way the Olympians have been trying to give directives to rule their descendants from afar) and she cursed the Godline with infertility (only allowing pregnancies in those she approves of for some reason). Godline magic is disappearing because the gods have terrible attention spans and the more time that passes, the more they forget to bless the few births that do happen (even though the gods are pissed at their descendants, they're also pretty vain and enjoy flaunting the talents of their descendants.)
So yeah...I'm trying to figure out how to get the essence of that across, understandably, in a phrase or a sentence.
The Godline population has since dwindled, victims of a cursed war, and their magical gifts have become rare.