Yan Martel's novel, Life of Pi, introduces character in a couple of different ways. Since the narrator is also characterized in the story, he is involved intermittently throughout the narration as Pi's story unfolds. This technique seems to place the narrator in the story, but he's not actually a part of the story. That is to say, there is a story within a story, which produces a different effect between the narrator and Pi, as well as with the audience and the narrator.
Pi, on the other hand, is presented by the narrator, but also presents himself through his own perspective. Then, Pi presents other characters in the story, from his perspective as well, which begs the question, "Whose story is this?" Along the way, Pi presents animals as characters in his stories. The animals seem to be so real because of Pi's personal expertise on how each animal reacts in different environments (i.e. zoo habitats vs. stranded on the ocean). And with one of the greatest twists in literature, the animals are presented at the end as possible human substitutes to an alternate ending, which ultimately finishes with calling into question the story as a whole. If the characters aren't who or what Pi said they were, then the element of characterization shifts and challenges the reader's mind. Overall, it is brilliant!