Characters need two things before they can act and flourish on their own: traits and

The answer is trait and context.   It means that they need to justify the character to bring out the reality on it. They would only be like a simple story that read. If characters don't have the feel and natural way of acting their role and believe that they are the character themselves, they won't be able to pull it off.  The life of the story depends on the character.

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