Otakuthon evolved from the annual "Animethon" anime marathon presented by "Otaku Anime of Concordia University", held at the Henry F. Hall Building on the Sir George Williams campus. The anime marathon had over the years, used one or several screening rooms, over the course of one or two days, and had included ancillary events. In 2005, the 10th edition of "Animethon" was renamed "Otakuthon". In 2006, "Otaku Anime" joined together with other local anime clubs and individuals to turn the annual anime marathon into a full blown convention.