The actual strength of the dark aeon's may not be canon, given they were just added as a extra challenge. the two things I dont get about the final aeon is, where is the fayth for each one, after all many summoners would have tried over the years. after all belgamine admits that she failed to beat Sin, so where is that fayth. also if seymoar's mother was made into an fayth in zanarkand why the heck is it in Baaj temple, probably hundreds of miles away. particularly as the place appears to be deserted for quite some time.