it's not like ffx/ffvii, since they aren't directly connected. what they did was took the bones of a general mythology, and each project put a different spin on it. (in ffxiii l'cie were people chosen by fal'cie to perform a specific task who would transform into monsters if they didn't accomplish it; in type-0 l'cie are people chosen by crystals to follow their will and could live for hundreds of years, if not forever. type-0 didn't have fal'cie iirc, ffxiii didn't have the concept of 'finis' which was a big part of type-0).