'The ones that ruled before'

Tbf, that's a major plot point of the game (if not the entire plot itself), rather than a "sidenote" (like Final Fantasy games - love them but they do that a lot).

I put it off for years and finally picked it up this past December and man I wish I'd picked it up sooner. May be my favorite gaming experience of the last decade. And I loved the direction they took with Aloy as a character. Can't wait to try Forbidden West soon