The fourth element Vogler mentions is the mentor. This is usually an older person with advice for the hero or heroine. The mentor can also encourage the hero or heroine to embark on the journey.
I'm not sure this figure is found in many of my stories. I can't isolate one in most of the romances I've written. I have found this character in most of the fantasies. There isn't one in the cozy mysteries either.
Of the mentor characters I've written in the fantasies, the yellow dragon in The Dragons of Fyre is my favorite. In The Henge stories, there is also a mentor in the figure of Doma Jandia. In some ways the evil Dom Senet is a mentor to those who follow him. Does the mentor always have to be a force for good? Is encouragement enough? Let me know what you think?
What about your stories? Do you have a mentor type character in them?