To investigate the possibility of entertainment to be a part of peace education for adults, the author wrote a Call of Cthulhu TRPG (CoC) scenario for this case study. The players who participated in this scenario afterward answered an open-ended survey. On the one hand, the survey results point to limitations of the current version of the scenario but also implied essential factors for developing and managing CoC TRPG scenarios and sessions for peace educational purposes. First, for effective sessions, the scenario needs to incorporate the main theme intelligibly for players. Second, letting players think about how their characters perceive social issues may help players rethink their views and contribute to raising awareness of an issue. Third, sessions benefit from adapting them to different formats of play: offline and remote play, voice chat, and text chat sessions.