Supporting roles should complement the protagonist well
For thousands of years, the supporting characters have been in a dark corner and are not eye-catching. This kind of thing can be done well in one word - a good death. If the supporting characters dare to outshine the protagonist, there is only one end - death without a burial place.
When Yuanyuan woke up and found out her identity as a supporting actor, she only had one thought: could she change her career to become a director?