Kosugi sports chin-length black hair and thick-framed glasses. He is timid at first glance, but upholds high ideals of what manga should be, breaking down when he tells Hattori that the mangaka he works with is using unscrupulous means to make his manga. He even admits that he read a lot of manga and did research on his own. Kosugi disagrees with his mangaka's means of generating manga or ideas for his manga. He is apparently the first editor to feel any sense of relief at his mangaka's decrease in position, due to Nanamine's means to make manga.