Archetypes are widely recognized characters or roles used in storytelling. These are the ones most writers focus on:
The protagonist is the main character in the story, the one who the main story arc is built around. He’s the “hero”, the one whose struggle is the driving conflict, and the one your reader should most closely identify with.
“The greater the villain, the greater the hero.” (I don’t remember who said that.) The antagonist is main character putting obstacles in the way of the protagonist. The struggle between the protagonist and the antagonist is the crux of the story, but the goal of the story is that of the protagonist (in case your antagonist is so well developed that there’s confusion between the two.)
The guardian serves as a mentor or teacher to the protagonist, providing information and support at key points in the plot to help the protagonist achieve the goal.
The tempter (or temptress, trickster, or contagonist) lives to inject chaos into the story, to draw the protagonist away from achieving the goal.
Reason is an adviser to the protagonist, always looking at situations from a logical viewpoint. Spock to us old Star Trek fans.
Emotion is another adviser, addressing situations from an emotional viewpoint. On Star Trek that was McCoy.
The faithful follower of the protagonist, the sidekick has an unshakable belief in our hero.
The counterpoint of the sidekick, the skeptic is a perpetual naysayer, always expressing doubts.
Note that these come in pairs: Protagonist vs. Antagonist, Guardian vs. Tempter, Reason vs. Emotion, and Sidekick vs. Skeptic. I think you’ll always find these roles in your stories, even if a single character fills several of them or the roles are all in the protagonist’s head. Splitting them out into several characters can simplify your writing and make your story more readable (and thus more saleable) so you might want to consider that before you get too deep in your writing.
Don’t you think?