10. His Existence Is The Result Of Creative Differences
You may have known the story as to how Dick Grayson became Nightwing, but not many fans have heard the behind-the scenes reason for the change.
Around 1982, Dick Grayson became a popular character in his own right as the leader of the Teen Titans. The writers behind Teen Titans at the time, Marv Wolfman and George Perez, made Dick Grayson grow a few years in age and maturity, making him smarter and less "punny" than his younger self.
While this character development granted him tremendous fan support, it caused friction within the corporate offices of DC Comics. Those who wrote the Batman titles desperately wanted Robin back but couldn't tamper with the continuity established by Wolfman and Perez. The Teen Titans writers weren't even close to budging, either.
So to compromise, Wolfman proposed that he would change Dick Grayson's superhero name to something else so that a new character could take up the mantle of Robin in his place.
This decision gave birth to not only the Nightwing persona but also to Jason Todd.