Co-GM is a free guild management tool designed for massively multiplayer online games, including Black Desert Online, Throne and Liberty, WoW Classic, and seven additional titles. It combines a Discord bot with a web dashboard to centralize administrative tasks that typically require multiple separate bots. The primary function of Co-GM is to provide guild leaders and officers with data analysis and organizational features, such as gear score distribution, class composition, attendance tracking over the last eight weeks, and roster management. The tool includes several specialized capabilities for supported games. For Black Desert Online, it offers gear optical character recognition (OCR) to scan and log player equipment, PvP analytics to track kill counts and war logs, artificial intelligence based fight analysis, and node war scheduling. For Throne and Liberty, the service operates through a sister site, throney.gg. Co-GM also features a logger for one-click war uploads, a kill heatmap, live Discord previews for guild applications, and build guides that display top player setups. The platform is updated weekly with a public roadmap, and new features are tested by officers before release. Typical use cases involve managing a guild across PvP seasons, world bosses, and guild missions. Workflows include uploading war data via the logger, reviewing PvP kill counts and heatmaps, scheduling node wars, and tracking member attendance and gear progression. The tool supports unlimited members and is designed to replace five to ten disconnected Discord bots with a single integrated system that understands game specific mechanics. Co-GM is run by real guilds and is currently fully shipped for Black Desert Online, with other games on a development roadmap prioritized by community demand.