Six top characters that benefit from the passage of fictional time

In ongoing book series, Jeff Somers notes, "characters often seem to exist in a strange universe where nothing changes and no one ages." Yet some authors choose "the route of unexplained immortality and age their characters over the course of a series." One such character:
Jack Reacher

Lee Child deliberately made Jack Reacher 36 years old when he started writing about him, saying that Reacher, “