Boss is not as hard as it looks. You just need full neptun set and beard. You need to caught him from up or down., so he can't hit you. Now you need to click "A" as fast as it's possible, until he gets critical hit. If he get, you need to caugh him once again. If you're running out of health (~50-100 left), use 5. spell and fight :) I hope I helped.
@blitzscrank
No, there shouldn't. It's the ense of the energy shop system, you must collect many energy to buy something. And it will be hard to implement.