All you need is all metabee's parts except his legs(needed to be a very high hp legs but not like burly)
then load up your medaforce to 80 and use ultra shot(sumbody else sayd ultimate shot, but that's wrong)
repeat this about 4á5 times and you will win

PS:you need to fight twice against him
1.
mega-emperor LEADER(? medal)
mega emperor(! medal)
mega-emperor(bear medal)
2.
mega-emperor LEADER(! medal)
mega-emperor(? medal)
mega-emperor(bear medal)