Mr. Sugarcube  

Kakuzatou-kun, 角砂糖

Gustavos, also known as Rubik in the light novels, works for the Daily Days and has been seen with a box of sugarcubes throughout the series. He offers one to the President of the Daily Days during the last episode, revealing his name as Kakuzatou-kun or Mr. Sugarcube. Despite not having seen the face of the President beforehand, Gustavos had to go behind the desk to give him a sugar cube due to the piles of books and papers on it.