Kingdom Hearts II Hardest Boss

Xaldin wasnt that hard because he was really predicable if you know how ...

 

Based on that I think your either talking about the six lance thrust which is fairly easy to dodge with quick run or the "fangs of dispair" bit witch I've never found a way to dodge. I even went as far as to bring high jump and arial dodge to level 2 (the highest you can bring it to at that point without cheating) and then he just barely clips you with it. You can block it with reflect, but you need to make sure you've got MP available. I also just noticed there are statues to hide behind granted I haven't tried that out yet.