Carl is a kind boy who tries his best to comfort those closest to him when he recognizes that they are in need. In the second season, Carl retains his shyness, but he develops a bolder personality and is seen to be less frightened of the world in response to the many ordeals he has experienced. 

Ellie is described as "mature beyond her years" as a result of the circumstances of her environment. She is characterized as strong, witty, and "a little rough around the edges".