During the Black Lives Matter (BLM) digital activism in 2020, Adorable Representative Master-of-Ceremony for Youth (A.R.M.Y.), a K-pop fan group for Bangtan Boys (BTS), initiated a movement to have BTS respond in solidarity with the Black members of the fan group (i.e., the Black A.R.M.Y. Lives Matter movement). The movement resulted in a large donation from BTS to the BLM movement. The goal of the current study was to apply intragroup process theories to describe the actions and experiences of a group of BTS fans, A.R.M.Y., in the context of BLM digital activism on Twitter. Particularly, this study aimed to address (a) how fans responded to the demands from movement supporters and (b) how they acknowledged each other on Twitter. Furthermore, based on the dual-identity theory, the study also examined how self-identified, dual-identity Black A.R.M.Y. expressed their opinions during the movement both (c) in their message contents and (d) in their pronoun use. Content analysis and text analysis were employed to answer the research questions. A total of 2,132 tweets were analyzed. Results showed that fans showed both sides of opinions, that is, standing in solidarity versus attacking the movement. The minority group and the allies continued to appeal to the majority by using strategies such as encouraging action and demonstrating Black pride and identity. We also found that self-identified dual-identity Black members tended to tweet using collective first-person pronouns "we," rather than "I." Implications on group cohesion, minority influence, and the black sheep effect were discussed.