Let’s talk about Dick Grayson, the original Robin and Batman’s sidekick. Eventually he would leave Batman and join the Teen Titans. From here he would develop a relationship with a whole new team of super-heroes while Batman would go on to recruit other Robins such as Jason Todd. He would even find a smoking-hot girlfriend Starfire, someone who would actually care about him with pure love. But this was not enough though, as Grayson had to find is own path and develop his own individual identity. Why did Robin become Nightwing though? What was wrong with staying as Robin?
The most clearest explanation is in New Teen Titans issue 39. When Flash (Wally West) decides to throw in the towel so he could go back to college, Dick Grayson decided to seize the opportunity by expressing his own thoughts. He says that Robin will always be associated with Batman and that he had been wearing the Robin outfit since being eight years old. He had since outgrown the role and is now a person with responsibilities. At this point he is not sure about his new identity but knows that he needs a new one. Cyborg wisely advises him to stop wearing short pants.
This all takes place during a story arc called The Judas Contract. Deathstroke The Terminator (Slade) has placed an infiltrator within the Teen Titans named Tara Markov. She goes by Terra, which I guess is a pun for terraforming. Deathstroke describes her as the best sociopath he had ever seen. She uses camera contact lenses to spy on everyone to make their secrets known and to make them vulnerable. I guess she had been sleeping with Slade since she’s naked in a robe the first time we see her as she’s talking to him and sitting on a bed. The Titans are to be captured, dead or alive, by HIVE and Deathstroke inherited the contract when his son died.
In Tales of the Teen Titans 43 we see quickly that Slade discovered Grayson’s identity as he crashed through his window in an attempt to capture him. After failing to fight his opponent Grayson decides to purposely fall out the window but uses his aerobatic skills to survive his four-story fall. An investigation shows that all the other Titans were captured. The next issue, 44, is particularly memorable because it shows the origin of Deathstroke. We also see Grayson as Nightwing for the first time. But why did Robin become Nightwing? He explains that the costume and name was influenced by Batman and Superman. (The name was previously used in Superman 158.)
So there you have it. Dick grayson had to grow up and put on his big-boy pants by retiring Robin for Nightwing. He did this mostly to get out of Batman’s shadow. As for the name, he stole it from Superman. If you are a comic book collector I recommend getting Tales of the Teen Titans 44 because it holds reasonable monetary value. Alternatively you should get your hands on The Judas Contract trade paper-back since you get to read the entire story and it’s more economical.