The Robot Circus is a group of seven robots in the 2003 series. They are Reno's surrogate family. Despite persecution for once being unlicensed robots, they become a featured, permanent attraction in the city of Bella Notte.
The group originally started as a travelling circus, owned by a human ringmaster named Mr. Bundt. After Bundt died, they were left stranded in a junkyard. However, after finding an abandoned baby, they were filled with motivation to keep going and to take care of him. They named him Reno, and took on street performing as a way to earn money for his care. At one point, they had enough funds to afford professional tents and a colourful bus to travel in.
When Reno turned 10, they allowed him to perform acrobatics with them while disguising him as a robot. They were extremely protective of him, out of fear that child services would separate take him away. When this was found out, they were pursued by the Bella Notte police, until Mayor Coward recognized they were talented and non-dangerous. After this, they became the official circus of Bella Notte.
The Robot Circus members, despite their status as unregistered robots, helped Reno grow up safely into a smart and healthy human. They love Reno very much, but knew of his potential as a child prodigy, and took the opportunity to get him legally adopted by Professor Ochanomizu in Metro City.
- Mr. Pannacotta: The robotic ringmaster, and Reno's stern primary father figure.
- Cupcake (Madeline in English): A beautiful acrobat robot who acted as Reno's mother figure.
- Cookie: A marching band performer who moves around on a built-in unicycle.
- Bonbon: A muscular, tan robot who can shoot fire from his mouth.
- Jellybean: A grey and black scarecrow who can remove his own head and toss it around.
- Marshmallow: A cute little clown robot who can elongate their neck and has springs in their feet.