Threshold guardians keep unworthy people from going through doorways and gates. They can be against the hero, indifferent to the hero or even allies but they will still always serve their purpose. No one goes onto the next stage before proven to be worthy. They can be thought of as bouncers, bodyguards or doorkeepers and represent ordinary obstacles people encounter in life such as prejudice, bad luck and opposition.
The mentor is the one who aids or trains the hero. They teach the hero, protect him and give him useful (often essential) gifts. The word comes from The Odyssey, in which a character named Mentor guides the hero. The mentor relationship often resembles that of a parent-child relationship. They are what the hero might become (and transcend) if he continued on the road of trails. They are the higher self, the wiser and nobler part of us.
The word “Hero” is Greek and it means “to protect and serve”. It is someone who would sacrifice his own needs to help others. In psychology terms, according to Freud, the individual consists of three layers. The it, the ego and the superego. The it represents desires and doesn’t care about right or wrong. The superego doesn’t care about anything other than right or wrong. The ego is left in the middle. It has the it telling it what it wants and the superego telling it what it shouldn’t want and the ego must mediate between the two.
The first step to character creation is research. You are not just creating a flat persona to fulfill a thingy that needs doing in your story, you are creating a person. As you are creating this person, you will get to know him in full detail. The reader will only see about 10% of him, the tip of the iceberg, but the writer should know him completely.