You've... never played a FF game before right? FF titles are all about 'being the good guys saving the world' - there is no 'evil side' to the story. If you're hoping for a WoW-style Horde vs Alliance factional war, or a Bioware style 'good/bad/neautral' character alignment, you will be sadly disappointed, as the FF series do not feature such ideas, and thus, neither does FFXIV.

Even alternative story paths do not usually occur in the series - FF games (like most JRPGs) are usually pretty linear.

In FFXIV, we're all on the same side really, we're all Hydaelyn's chosen against the Ascians, Primals and the Garleans - if you want the ability to play a bad guy, you won't find it here.