The protagonist's mission: to make sarcastic remarks, eat and drink until death, watch from the front row and sell melon seed soda with a small bench that stops by to be the boss of the month.
The supporting role's mission: Love the dog-blood to promote the development of the plot, and provide the protagonist with the opportunity to make sarcastic remarks, eat, drink, and wait until death. Watch from the front row, sell melon seed soda, and have a small bench to become the moon's elder.
So
Who is the protagonist and who is the supporting role (╯‵□′)╯┻━┻