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
Due to a crisis of conscience, Dick adopts the new villainous persona of Renegade in order to infiltrate Lex Luthor's Secret Society of Super-Villains. This ruse includes Nightwing aligning himself with his long-time enemy Deathstroke in order to track the manufacturing and distribution of Bane's venom serum and to keep tabs on the Society's activities in Gotham and Blüdhaven. He also begins training (and subtly converting) Deathstroke's daughter, Ravager.