This paragraph outlines the importance of characters and characterization in fiction. According to this writer, characters are the driving force of plot. They are the physical people, animals, or animate objects that inhabit the world the author has created. It is characters' actions and experiences that define the story.
You can see the examples this writer gives of Tarzan of the Apes and "A Rose for Emily," whose characters drive the action of the story. Without the figure of Tarzan or Emily, we have nothing to care about in these stories.
However, to make us even more invested as a reader, the author may also employ characterization. This a device an author uses to bring the characters they have created to full life and allow us to believe the illusion of reality that they have woven for us. Characterization could be created through dialogue, description, or action. Is this character talkative, introspective, brash, vain, solemn, reserved, or particularly afraid of spiders? There are infinite ways writers can paint their characters, but characterization is the tool that turns flat, lifeless characters into fully realized human beings.
It is this, the above writer suggests, that allows us to fully connect with fiction. Characterization turns the characters into beings we can connect with and relate to and in whom we can recognize a part of ourselves. In this way, a writer's work is able to come alive in the reader, and the reader is able to immerse themselves entirely in the fictional illusion the writer has woven for them.