This even happen after you stop fighting? Well, in anycase the other aeons are Yojumdo, Anima and the Magus Sisters. Now if you don't know where to get them this is how (note I suck at this so...).
Yojimdo
Is the stolen fayth and is found on the way from the clamlands to Mt.Gagazet(forgive my spelling).Now when you get to where it say clamlands near bridge go on the path the goes under the second bridge. There's a cave there near the save point and I think you get the rusty sword there also (not sure about that though been a while).
Anima
Now she is found at Baaj Temple you need to get all hidden chest from the other aeons (not counting Yojimbo or the sisters) using the destruction ruins to find them.(I thinks that covers that).
Magus
Now this you well need to get the Blossom crown from the guy who runs the Arena then you need to beat all the aeons up to Anima then you get the Blossom scepter. With this you can now get the Sisters now after beating the Sisters you will be able to send her (there i think that right someone fill in what i messed up or forgot to put in)
well i hope this helps