A robot that worked as a maid at Yuusaku's house. Built and programmed by Yuusaku, Roboppi is very loyal and respectful to him. Yuusaku cares and visibly has a fondness for his house-cleaning robot, as he smiles warmly and pets Roboppi affectionately as in his flashbacks. However, Roboppi does describe Yuusaku as being "a little cold-hearted".