Quote Originally Posted by Theodric View Post
To the second point, Elder Primals differ from regular Primals in the sense that once they're summoned they don't need to absorb aether or prayers from their surroundings.
The evidence seems to indicate they do still need prayer. Bahamut and the Warring Triad had their followers sealed with them to continue feeding them prayers, Hydaelyn had worship from across Eorzea, and Zodiark still had 3/4 of the Ancients' souls sealed with him on the moon.