how do you beat that demon dude at the end of the world??

Theres no cheat needed
Ok first battle summon tinkerbell(plz tell me you have oblivion)it works best.just go up and hit him but when he says insolent fools run and when he comes closer and says sumbit roll backwards and then go hit him.(just repeat this as needed)
Second match hes that big thing you fought on your island before you went in the portal.So he should be easy.
Third match hes the dude in the first match again.he has newer attacks so when he chargese like those pirates just roll left or right. And get close and hit em when he says ongaurdian backup some and use aero(or uprgraded version.) Use cure if needed make sure you have megalixers and hi-potions cause you will be in like a never ending battle.that is after you beat him four the third time.(did I mention the second and third matches yourby yourself. I hope I helped

Hey, you talking about the chernabog? That thing at the world "End of the World" after you read that message in hallow bastion after when you go through all the worlds? Lol if thats wut you're talking about listen here! The key is defence. Use areo and cure for magic only. When you attack him, attack from the back of his head. Just try you're best! Hope this helped.

Flutey_Tutey