Snipped from [Full Interview]
Fusionx: What is the difference between a Primal and an Elder Primal?
Koji Fox: Basically it’s all a matter of
length of worship. With primals, it’s all about how you have someone worshiping you and you become that primal and they believe in you and you get your power from that. For the Ixal or the Amalj’aa, it’s the belief that makes the aether combine to summon forth these primals—so when you look at Ifrit, and Titan, and the one’s we’re calling primals, they’re considered very young. They’ve been believing in them for a long time, but looked at in a span of
all the eras it’s not that much time.<...>
Anwyll: Originally, we thought it might be more complicated than that, <...> but it’s just has to do with the
length of time?
Koji Fox: Basic length of time.