Ninja was a robot from the United Kingdom which competed in Season 1.5, the debut of This is Fighting Robots. Under unknown circumstances, it was selected by a celebrity to reach the main competition.
Ninja is a 'thwackbot', driven by two large tires at either side of the robot. It was armed with a large sword, which swings overhead courtesy of the robot's drive power, and delivers attacks in this fashion. As a thwackbot, Ninja is also invertible.
This is Fighting Robots (Season 1.5)
Ninja was not initially chosen by the celebrities in their initial selection process, requiring Ninja to fight in a four-way rumble, in order to impress the celebrities. There, Ninja faced 008, Saturn and Xiake in a battle that would ultimately not be aired in the programme. Although it is unknown whether or not Ninja was selected by a celebrity during the battle, it nevertheless advanced to the main competition after being chosen by a celebrity.