There are four canons that have formed. One being based on the first two films and video game, another based off the Real Ghostbusters and Extreme Ghostbusters and related media, as well as one forming based on the reboot 2016 film. While there are three clear paths, IDW comic series has formed its own canon which ties most elements from other canons via multiple dimensions.
Other Possible Canons
- Ghostbusters Movie Canon (Before 2009) - Before Ghostbusters: The Video Game was released, previously Ghostbusters: The Return (Novel) was considered canon. However, events in the two media conflict and therefore the novel was removed from the canon, favoring the game.
- Ghostbusters Unified Canon - Developed in fan circles as way to merge the Movie and Animated canons. It takes elements from Ghostbusters, The Real Ghostbusters, Ghostbusters II, and Extreme Ghostbusters and removes or adapts the timeline to match between The Real Ghostbusters and Ghostbusters II, which conflict. The canon conflicted with Ghostbusters: The Video Game, and ultimately was retired in most circles when the IDW Canon introduced the multi-dimensions concept.
- Marvel UK The Real Ghosbusters Canon - A canon based around the Marvel released The Real Ghostbusters comic book series, it favors the comic with additional canon from Ghostbusters, The Real Ghostbusters (series), and the Kenner The Real Ghostbusters toys (sometimes also trying to add Ghostbusters II). This canon was barely used by fans in parts of Europe during the late 1980's and 1990's due to the comics loose continuity within it's own story-line. It is assumed that the interest in the canon ended by the late 90's.