>>14753398
There are 15 known planets(so far), each planet has its own storyline and the storylines of games are usually hundreds of years apart. The only thing connecting them is the magitek who have created dimensional/time travel and tries to conquer each planet, also Final Fantasy 10 is connected to Final Fantasy 7, a boy named shinra apparently gets sent to ff7's gaia(or their earth) and forms the shin-ra electric power company, losely based off of the magitek company technologies.