NOS-4-A2 is arrogant; even more arrogant than Zurg. He was created and programmed to destroy Buzz Lightyear and Star Command, defeat not being in his programming. He flaunts his position and power, employs the use of minions to do his bidding, and after his first "failure" becomes his own villain, no longer taking orders from Zurg.
Buzz's little brother since they share a father, Zurg.
Nos-4-A2 used to be Nikolai Lightyear before Zurg killed him and forced him into a robotic body.