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
During the events of the "Battle for the Cowl", Nightwing is said to have become unapproachable and less emotional. He is seen by the Bat-Suit display cases, still mourning the loss of Batman. Nightwing is said to be resisting the idea that someone needs to take up the mantle of Batman, in spite of arguments from Robin and Alfred Pennyworth that it is necessary. It is later revealed he has no objections to becoming the new Batman, but was ordered not to in Bruce's prerecorded message for him, saying that Nightwing and Robin could carry the torch.