The second Biscuit robot created by the professor. His appearance is similar to the old model Biscuit No. 1, the only difference being the number of the hat. Unlike Biscuit No. 1, Biscuit No. 2 was built with the intention to speak. (Source: Wikipedia)
A coal miner, and one of Jörmungandr's and her sister's 5 fathers. (They adopted them)
The main characters homeroom teacher. Shown to be very witty and banterous. His hatred for Sasazuka-kun is also very clear from episode two.
A factory robot, who can produce many items from her arms, and repair the robots if they get broken. She is also able to mimic voices, and often gives a wry response to her friends' comedic efforts.
A Maid-type robot, although there are no humans left for her to serve. The other robots describe her as Moe; she is earnest and always put-upon to attempt jokes.
Azusa is Sho's best friend, and she accompanies him through his many travels with the "Superbook"!