The Mushroom Kingdom is about to bow down to their new ruler!
~ The Robot Princess, greets her subjects while grinning evilly.
The Robot Princess was robotic double of Princess Peach Toadstool, ruler of the Mushroom Kingdom. The character makes her debut in the Super Mario Bros. 3 episode Rain Storm, where she is the main antagonist. She does not possess any powers at all, besides manipulation, and therefore, she sides with King Bowser. She is always capable of trash-talking to her subjects.
The Robot Princess was created by Bowser's subjects to take over the Mushroom Kingdom while the real Princess was away on vacation. The Super Mario Bros were assigned to take over the kingdom, but feeling overwhelmed, King Bowser thought it was the perfect moment to bring in the fake princess. The Robot Princess was actually assigned with her own cruel and crazy personality and hasn't malfunctioned since.
While she was in power, she made very risky and villainous degrees which shook the kingdom down. Such as creating a quicksand highway and watering all the Fire Flowers in the kingdom, (possibly to prevent her own defeat if Mario & Luigi found out). Mario and Luigi were unnaware that she was an imposter, or even a robot, but they did get suspicious that she came back so early from her vacation, and that she didn't have a sun tan. She also had black lipstick and spoke with terrible grammar.
Before her defeat by the real Princess, she almost handed the Kingdoms (She got hold of the real Princesses Crown) throne to Bowser. She also potentially fired both Mario & Luigi as her right hands. She was later completely drenched by a huge torrent of water created by the real Princess, which caused her to malfunction and freeze, creating a fried circuit as she was a mechanical being. After her defeat, she is seen lying down with electric sparks, it's unknown if she's destroyed, but she probably was as her circuit would have been shorted.