Nightwing
Although Nightwing is commonly associated with Batman, the title and concept have origins in classic Superman stories. The original Nightwing in DC Comics was an identity assumed by alien superhero Superman when stranded on the Kryptonian city of Kandor with his pal Jimmy Olsen. Drawing inspiration from Batman and Robin, the two protect Kandor as the superheroes Nightwing and Flamebird. Following the Crisis on Infinite Earths continuity reboot in 1985, Nightwing was re-imagined as a legendary vigilante from Krypton whose story inspires Dick Grayson's choice of name when he leaves behind his Robin identity.
Nightwing
After the events of "Flashpoint" as part of The New 52, "Nightwing" was relaunched with issue #1. Grayson resumes the role of Nightwing following the return of Bruce Wayne. The new series, written by Kyle Higgins, opens with Grayson having returned to Gotham, when Haly's Circus comes to town. Through a series of events, Grayson inherits the circus and is working through internal struggles with his past as he investigates the secrets the circus has brought about.