Hideo Sotomura is one of the students of Class 1-D who is seated in the leftmost seat in the third row behind Yōsuke Hirata. Hideo seems to blend in the background quite a bit, as he is neglected from the main events that seem to happen in Class 1-D. However, he does seem to capitalise on the opportunity, seeing the sense in helping out Argos team in their mission. Hideo is an otaku in nature and is often heard using archaic Japanese to speak to his classmates. He collects and observes information every day, ranging from an interests of bishōjo game to manga and animation.