I love these kinds of stages where you have different characters in the background watching you fight your opponent. They should have animation too. For example if you knock an evil character to the ground a light character will cheer you on and vice versa. Maybe a fight may even break out between a light and dark character in the background if the primary battle gets too intense. Also, have the Dragon King watch as you fight the sub boss. And have the DK and the sub boss stand next to each other in the background of a secret character battle, taunting you.