There are three games or story routes in the Fire Emblem: Fates storyline: Birthright, Conquest, and Revelation. Together, they present different perspectives on Corrin's conflict between Hoshido and Nohr.
Birthright follows Corrin after choosing their biological family in Hoshido, while Conquest follows the choice to remain with Corrin's adoptive family in Nohr. These two versions offer different maps, objectives, characters, and story developments. Revelation is a third route in which Corrin rejects both kingdoms and attempts to unite them against the hidden threat manipulating the war.
The number can be confusing because Fates was not released as three ordinary standalone games. Birthright and Conquest were sold as separate physical versions, while Revelation was originally released as downloadable content. A special edition included access to all three routes.
Each route is substantial and has its own campaign, so “three” refers to the three distinct Fates storylines rather than three unrelated entries in the wider Fire Emblem series. The three-route structure was designed to let players explore different sides of the same conflict.