Try and keep his core open at all times, he'll just sit there and countdown instead of attacking, alot easier to mitigate. This is 100% a magic fight unfortunately, if you can manage to bring either water magic or holy magic DD, this will have an easier time. I ended up using Meia BSB and Rydia BSB2/OSB (OSB didn't do much) as my DD, both of which I got from AA volume 9.
XI Wiki



