Unlike many other stories, Lewis' The Lion, the Witch, and the Wardrobe does not have just one single main character. In fact, it has multiple. At the beginning of the story, we meet the Pevensie children: Peter, the oldest; Susan, the next oldest; Edmund, the second youngest; and Lucy, the youngest. Although all the children are important to the story, Lucy is the one we hear from the most. She is the first of the children to go into Narnia through the wardrobe, and she meets a faun named Mr. Tumnus while she's there; and then when she returns with her siblings, it is upon her urging that they venture off deeper into Narnia in order to search for her missing friend.
However, the main hero of the story is Aslan, a lion and the king of Narnia. Because of his self-sacrifice, allowing the White Witch to kill him, Edmund is saved from the White Witch. When he returns to life afterwards, he is responsible for destroying the White Witch and removing her from her seat of power.