There is no doubt about it, this is a very challenging fight. However, with good communication and enough practice, he is definitely defeatable.

Below is a video guide created by Mr Happy. Although it is rather long, it covers everything that happens in the fight, and even replays the main mechanics a few times. At the very end, there is a complete play through of the entire fight, without any interruptions.



For those who prefer text, this is a written guide to his various moves and the order in which he uses them:

http://ffxivwiki.eorzeaendgame.com/The_Navel_(Extreme)