John Diggle is more than just a popular character in the show; he is an homage to Andy Diggle, the veteran comic book writer who had written on many of DC's most popular comic books, including a Green Arrow mini-series which would become influential to the show - Green Arrow: Year One. Much like Frank Millers Batman: Year One, the comic reinterprets the characters early career and embraces the darker and more adult tones, as well as grounding it in a sense of reality. The comic focuses on Oliver Queens time on the island, his rescue, and how he readjusts into society the same themes that dominate Arrow. Without Andy Diggles story it is unlikely that a network would commission a show based around the adventures of Green Arrow, so it is fitting that in nearly every episode there is a nod towards the man who enabled this immensely successful show to exist.