The most passionate fans of fictional properties are rarely satisfied with consuming them passively. Fanfic, the convention circuit, cosplay, and yes, roleplay are all ways that fans engage with their favorite shows, movies, and books, and it’s no surprise that tabletop RPGs based on fan favorite licenses have become immensely popular. Engaging with these licensed games can pose challenges, though. Every fictional world, be it that of Star Trek, Star Wars, Discworld, or Marvel, has a body of work upon which it’s based; this body of work is referred to as its canon. While the definition of canon dates far back and has roots in Christian theology, canon as we nerds typically refer to it is most directly traced back to Arthur Conan Doyle and the Sherlock Holmes stories. Sherlock Holmes was an immensely popular character and also an early example of a character who was the subject of fan fiction, or fanfic. Sherlock Holmes is also the first example of trouble with canon, as there are Doyle-penned works which are not necessarily considered ‘canon’ Sherlock Holmes stories. Arguing over canon is one of the pillars of nerd discourse, propped up by numerous comic book retcons and bigger events like the recent revision of the Star Wars canon by Disney. To say the least, the arguments don’t necessarily stop when we sit down at the gaming table.