Social anthropologist and novelist. Graduated from college with degrees in anthropology, women's folklore, human sacrifice, and post-war manga. In addition to his work with manga he is a critic, essayist, and author of several successful non-fiction books on Japanese popular and otaku sub-cultures. One of his first animation script works was Maho no Rouge Lipstick, an adult lolicon OVA. Otsuka was the editor for the bishojo lolicon manga series Petit Apple Pie.

In the 80s, Otsuka was editor-in-chief of MANGA BURIKKO, a leading men's manga magazine where he pioneered research on the otaku sub-culture in modern Japan. In 1988 he published "Manga no Koro" (The Structure of Comics), a serious study of Japanese comics and their social significance. Also as critic, Otsuka Eiji, summarized the case of the Japanese red army's 1972 murders as a conflict between the masculine and the feminine principles as they were both embodied by women and against women (Otsuka,1994).

Married to fellow mangaka SHIRAKURA Yumi.