Rikuo's friend. At first glance he seems to be a bit of a delinquent, but in fact he's a merit scholarship student with aspirations for law school. He's studying the Laws of Robotics, and is quite knowledgeable about the legal aspects of robots, but for some reason doesn't have one at home. His personality is the opposite of Rikuo's, which enables them to have a good friendship. Everyone calls him Masaki, but it is revealed later on that his actual name is Masakazu. (Source: Official Website - English)
It is later shown that he does in fact own a robot at home and the issues that followed it.