Quote Originally Posted by Kyrel View Post
When someone becomes a fayth their body will be lying forever on a stone. Summoners go on a pilgrimage and beg the fayths for their aid. The fayth can manifest themselves physically through their Aeon form.

Some argue their physical form can appear multiple times in different places, but I never thought so.
Well, if I remember correctly, you can't summon Ifrit while fighting and Ifrit and so on. As for their strength differences, the power comes from the summoner and stuff.