Characters that grow and change

One last important point about characters in stories: they can change over time.

For instance, here are the main characters from Harry Potter and the Philosopher's Stone (or Sorceror's Stone, in the U.S.):

tween-age Harry, Ron and Hermione, well groomed, wearing school uniform, looking innocent

And here are the same characters by the end of Deathly Hallows:

Harry, Ron and Hermione as young adults, wearing denim and leather, covered in grime and blood, leading a large group of students and teachers

Time and stories change us all.

Jonas Hill saying that's really deep