Dagorhir is one of the largest and oldest documented live-action roleplay groups. Dagorhir organizers have published multiple game regulations via handbooks with much emphasis on costumes since the 1970s. Dagorhir facilitates community building, identity negotiation and creative storytelling that expands beyond the game through transformative play. In our research, we examine how these costume regulations have influenced fantasy character and real-world identities, how the regulations have influenced perceived costume authenticity over time and how the handbook regulations have engaged with power dynamics related to intersectional identities. We analysed costume-related content in the three handbooks while drawing upon content analysis and historical methods. We found that as the regulations evolved since the 1970s, the rules increasingly centred costumes, indicating the prominence of costume in this escapist community. However, while these spaces centred on the costumed body, Dagorhir regulations reinforced oppressive intersectional norms. Our work has implications for society and business, that is, our findings can help individuals understand why people participate in live-action roleplay, which may reduce stigma surrounding this activity. Additionally, costume producers and retailers can make informed business decisions based upon our findings. Last, live-action roleplay communities can utilize our findings to reject oppressive written and unwritten regulations.