The 100

The character Octavia is only 14 in the books, much younger then her age of almost 18 in the show.

Many of the young characters' names are taken from notable science fiction writers: Clarke comes from Arthur C. Clarke, Wells comes from H.G. Wells, Octavia comes from Octavia Butler, Bellamy comes from Edward Bellamy. Many of the younger characters who aren't named after science fiction authors are characters that were created for the series, who aren't in the source novel.

On the original script, Raven was supposed to be Finn's mother but decided to make her more like Glass from the novel and Bellamy and Octavia's surname was Blake.