Whenever a script or story is written the people in the script are called the characters in the story. When a breakdown of characters is sent out by a casting director that is one of the first things you see and it is the basis for the casting director to accept auditions for those parts.
So what makes up the Character? There are three truths that an actor has to create to become competitive in auditioning for a part. Those truths are the Physical Truth, Verbal Truth and the Emotional Truth. The tool the actor uses to create these truths are the Actors Instrument which is made up by the following things. Your Body, Hair, Voice, Eyes, Coloring, Imagination, Energy, Clothes and Timing. Those are all external things except for your Imagination and that is what is used to create the Emotional Truth which is incredibly important in an audition because that is what creates the Human Qualities of the Character. We all feel and respond emotionally to given sets of circumstances. That motivation created by the emotion creates the quality of the character. Creating the Emotional Truth of the character is what makes your eyes come alive and your body to react accordingly to the emotional experience the character is experiencing. It is what causes you to use your voice in a specific way to fulfill the script verbally.
All these things, when used properly, is how we create the humanity of the character because in the character’s world they are human. On the page of the script they are fictitious and it is the job of the actor to create their humanity. How you connect the character to the other character or characters in the script is for another class but here is a hint. It’s what you want to do to them using the dialogue!