OK. here's what you do. Using Zero, use that air slanting slash on his mouth when it is open. This is his weakness. constantly destroy the green things for much needed health. When he opens his mouth, lay it on him. Using X, use the Ultimate Armor, and hit it with buster shots. Constantly abuse the nova strike to dodge the Black hole thing (you can do it if you do it at the right time from under the mouth). Nova Strike when he is using the green things to destroy them faster. When he starts blasting at the ground, jump and shot as you move out of the way. That should be about it.

Sorry, this meant to go in the Sigma X6 thread. I probably hit the wrong button or something. I am new to this site, so I haven't quite gotten everything down yet.