>>714223693
Both FF1 and FF2 are Kawazu's games, yes, SaGa is more relevant to those two and a better successor to both than the rest of FF is, but it's still very much its own series at the end of the day.
SaGa and Mana are also sister series that intermingle with each other quite a bit, Frontier has many Mana cameos from the Thunder Dragon to Rabis, Minstrel Song has a questline that reenacts the Red Mage's section from FFA and so on, both were born because their creators didn't want to work on FF anymore but got to keep working on things that they first implemented in those games.