Chaosium

Chaosium is an American game publisher founded in 1975 by Greg Stafford in California. Its first major release was White Bear and Red Moon, Stafford’s board game about the mythic continent of Glorantha. That setting became the foundation for RuneQuest, a roleplaying game published by Chaosium in 1978. Designed by Steve Perrin, Ray Turney, Steve Henderson, and Warren James, RuneQuest replaced traditional character classes with a skill-based system and used percentile rolls for resolution. Its distinctive rules for hit locations, armor, and active parrying influenced later roleplaying designs. Stafford’s Glorantha was not merely a backdrop: it presented competing cultures, religions, and histories as central parts of play. Chaosium’s best-known property is Call of Cthulhu, first published in 1981. Sandy Petersen designed it using the Basic Role-Playing system and adapted the fiction of H. P. Lovecraft and related writers into investigative horror. Rather than rewarding combat and conquest, the game emphasizes research, clues, social investigation, and the psychological cost of encountering the Mythos. Its Sanity rules made mental deterioration a formal game concern, helping establish a lasting model for horror roleplaying. The company also published Pendragon, Greg Stafford’s Arthurian roleplaying game, originally released in 1985. Pendragon tracks a knight’s career across generations, connecting personal traits, passions, family inheritance, and the changing history of Britain. Chaosium published several important editions and supplements, while later editions appeared through Stafford’s company Nocturnal Media and other publishers. Chaosium has repeatedly returned to Glorantha, publishing new RuneQuest material and related games such as HeroQuest and 13th Age: Glorantha. In 2015, Moon Design Publications merged with Chaosium, bringing designers and executives including Rick Meints into the company’s leadership. Greg Stafford returned to Chaosium in an active creative role, and Sandy Petersen also rejoined the organization. Its modern catalog includes the seventh edition of Call of Cthulhu, RuneQuest: Roleplaying in Glorantha, Rivers of London, and board games tied to its settings. Call of Cthulhu has become a major international roleplaying title, translated into numerous languages and supported by campaigns, scenarios, fiction, and licensed adaptations. Chaosium’s significance lies in connecting literary horror with investigative play, while also preserving Glorantha as one of tabletop gaming’s longest-running original settings. The company’s games are notable for treating setting, worldview, and character identity as mechanics, not decorative background alone. That design tradition remains visible in its contemporary publications and in the many creators influenced by Chaosium’s work across tabletop roleplaying games and horror.