WARNING!!
Final Fantasy XI is a game that was released in 2002, however the story might not be as well-known as other entries due to it being an MMO.
Because of this, there's elements to the story you may be unfamiliar with!
I can't stress enough how you should experience the story firsthand if you're even a little interested in it! There's plenty of plot to chew through, with characters to enjoy and hate, and places to explore.
If the Bahamut world is open by the time you're reading this as well, Resaae herself wouldn't hesitate to help you through the story! The hardest part about FFXI, in my opinion, is just getting into the game when starting out, and many players are filtered pretty quickly.
Proper spoiler warning: each expansion is separated by their respective tab, however, each will build on top of the previous expansion's information. For instance, Chains of Promathia will heavily deal with reveals from Rise of the Zilart, etc., so it's highly recommended to read them in order of release.
Someday I might do an add-on section, but just setting this part up is pretty huge on its own, so I'm satisfied for now.