Nightwing (real name Richard "Dick" Grayson, born December 1st, 1996) was the first Robin. The former protégé of Batman, Nightwing was a founding member of the Team. He currently leads the covert operations team, and acts as a mentor to the current Robin, Tim Drake.
In his early days as Robin, despite being only 13, he was more experienced than his fellow sidekicks. By then he had been training under Batman's wing for four years. Despite Batman's influence on Robin, the two have very contrasting personalities. While his mentor was cold and very serious, Robin's demeanor was quite the opposite. Robin was naturally a very lighthearted individual who seemed to take joy in nearly everything that he did. Despite his immaturity, he could get along very well with people who were older than him, and tended to act more maturely whenever he was tasked with a certain level of responsibility.
When simply interacting with his friends, Robin behaved in a jovial and oftentimes "little brother"-like role, in which he joked freely about his teammates, and even made fun of them when they made mistakes. He had a particularly close friendship with Kid Flash, with whom he was able to joke and often treated like a brother of sorts. Robin also seemed to take great pleasure in creating back-formations, by removing prefixes from commonly-used words such as "disaster", "distraught", "overwhelmed" and "infiltrated" to create new words.
Despite his child like behavior at times, Robin was a natural tactical thinker, often coming up with plans for the Team on the fly, and figuring out complex situations faster than many of his teammates. He was also very pragmatic and preferred to think ahead. During the Team 's brief scuffle with Guardian, Robin took the liberty to activate the elevator to escape instead of fighting alongside his Team, had no qualms about Miss Martian delving into his mind to retrieve his memories, and took a break from running from Red Torpedo and Red Inferno to download the Cave's blueprints.
Robin initially considered himself to be the natural leader of the Team, citing his longer experience as a hero. However, this experience and his strong working relationship with Batman led him to mistakenly assume that the other members of the Team would understand and follow his plans without him explaining them. This unfortunately caused problems on their first mission against Kobra and Bane. He subsequently claimed that Aqualad would be a better leader for the Team. While Aqualad accepted the role, he stated that both he and the rest of the Team expected Robin to eventually take the mantle, due to the fact he was more suited for the job.
After the trauma of watching his teammates die in a simulation, Robin opened up to Black Canary during a therapy session. He did want to be the leader and wanted to someday become Batman. But after sending his friends to their "deaths" in the simulation made by Miss Martian, he no longer desired to become like Batman, willing to sacrifice everything for the sake of the mission. Despite this, five years later he demonstrates these traits as team leader.
Dick has matured considerably over the intervening five years. As Nightwing, he is more driven and focused—just like his mentor. While he had a moment of levity in congratulating Robin's success in his first mission as squad leader, Nightwing has reined in the wisecracks, and has become much more somber and serious. A different side to him is what makes Wally call him a "dog"—he has had relationships with multiple girls, including Zatanna and Rocket, and all are still on good terms with him. When asked, he has commented that it was his superpower.