Sadly the Gameplay Guide offers the best advice I can think of. I had to do that fight about 20 times before I finally beat it.
I recommend getting his health as low as possible and as fast as possible with some dragons to distract him initially. If he kills your dragons before he goes into "crazy fast" mode, you aren't doing it fast enough. Try using some food that boosts magic power.
Make sure when he fires off the missiles you are jumping toward him and then on your double jump away from him. Have some good food on standby for when you CAN actually use it. The real trick is getting lucky enough with the camera angles and his sequence of attacks to burn him down before he owns you.
When I finally beat him the fight only lasted about 2 minutes and he only used missiles twice.
Last edited by Skyripper; 02-27-2012 at 05:26 AM.