This paper analyzes the relationship between agencies and artifacts represented in
ethnographic case studies of ten female informants aged 20–25 participating in the cos-
play community. Cosplay is a female-dominated niche subculture of extreme fans and
mavens, who are devoted to dressing up as characters from manga, games, and anime.
“Cosplayers” are highly conscious of quality standards for costumes, makeup, and ac-
cessories. Cosplay events and dedicated SNSs for cosplayers are a valuable venue for
exchanging information about costume making. First we frame this work as an effort
to think about their agencies using the concept of hybrid collective and activity theory.
Then we share an overview of cosplay culture in Japan and our methodologies based on
interviews and fieldwork. Using SCAT (Otani, 2011) methodology, we group our find-
ings in two different categories: (1) Cosplayers’ agencies and relationships with others
mediated by usage of particular artifacts, (2) Cosplayers agencies visualized through
socio-artificial scaffolding and collective achievement. We conclude that cosplayers are
producing and standardizing available artifacts for their cosplay objects, and in doing
so, they are designing their agencies. We consider that the activities like them are one
appearance we can observe in the other our mundane communities not apply only to
cosplay one. Not only to cosplay, however we consider that these kinds of activities
apply to other mundane communities.