The problem is the final boss Balthazar.
Once Aurene(blue dragon) appear, you need to base on her. She will cast a blue circle and you can press "-" there, for an attack to stun Balthazar's critical attack. She will also cast blue bubble during the fight to give u shield. But it is subject to AURENE IS NOT PRISONED.
End and good luck....
p.s. you may experience become naked after the fight like me lol