Canon Verse

The fanfic is set in the universe of the source material. As it can sometimes be difficult to determine when a fanfic is set in canon and when not, certain rules depending on the source come into play.

In Supernatural (Destiel):

If the fanfic is set in canon, magic and supernatural creatures exist, Dean is a hunter and Castiel is an angel as they are portrayed in the show. (More info about this can be found in the description of the Creature tag.)

In the Hobbit (Bagginshield):

Here the distinction is rather difficult, as Thorin and Bilbo are still beings of Middle Earth in many Alternate Universe fanfics. Distinguishing canon from AU based solely on what they are is therefore impossible. Instead time is important; canon Bagginshield fanfics involve everything taking place from the moment where Thorin and the dwarves arrive in Bag End until Thorin dies in the Battle of Five Armies. Everything taking place after or before that (for example Bilbo going to Valinor to get back Thorin) would not be canon.

In Hazbin Hotel / Helluva Boss (Stolitz and RadioApple):

In this fandon, similarly to the Hobbit, you can't simply define canon based on species, but additional facts need to be met to count as canon. In order for a Stolitz fanfic to be set in canon, Blitz needs to be an imp and be an assassin, formerly working in a circus as a child. Stolas needs to be a Goetian Prince who lend Blitz the Grimoire so he can travel to the human world. In order for a RadioApple fanfic to be set in canon, Lucifer is the devil and King of Hell and Alastor is a sinner overlord, who is the hotelier of the Hazbin Hotel.

In Sherlock (Mystrade), Stargate Atlantis (McShep), Marvel (Ironstrange, SamBucky, Lokius), Good Omens (Ineffable husbands), Shadowhunters (Malec), Yuri on Ice (Victuuri) and Our Flag Means Death (BlackBonnet):

In these fandoms the distinction is rather simple. If the fanfic is set in canon, Mycroft is working for (and is) the British Government and Greg is working for Scotland Yard. Both John and Rodney are working for the military and are on Atlantis, Tony is Iron Man and Stephen is a Master of the Mystic Arts, Sam is the Falcon (or Captain America) and Bucky used to be the Winter Soldier, Loki is the God of Mischief and Mobius works for the TVA, Aziraphale is an angel and Crowley is a demon, Alec is a Shadowhunter and Magnus is a Warlock, both Yuuri and Victor are figure skaters, Stede and Ed are both pirates in 1717.

In summary, if you can put the fanfic into the show or the film without having to change anything and it still making sense, then the fanfic is set in canon. It could potentially be another episode or a scene in the film.

Find fanfics

Alternate Universe

The fanfic is set in an alternate universe, meaning the characters have different jobs or live in different places or are different beings. In a nutshell, anything is possible in an AU fanfic.

Find fanfics

AU - Erebor never fell

The fanfic is set in a universe where Erebor never fell and Smaug either never showed up or was defeated. This tag can only be used for Hobbit fanfics.

Find fanfics

AU - Regency / Historical

The fanfic is set in the Regency era or in the Victorian era, so around 1811 until 1901. It is however of course also possible that the fanfic is set even earlier than 1811.

Find fanfics

AU - High School

The fanfic is set in a universe where one or both characters are in High School, either being students or teachers.

Find fanfics

AU - No Magic / Human

The fanfic is either set in a universe where magic doesn't exist or the main characters are human, even though they aren't in canon. This tag is primarely used for Destiel, Ineffable husbands, Malec, Bagginshield and Lokius fanfics.
Note that even though most fanfics with this tag are both set in a universe with no magic and the characters are human, only one of the conditions needs to be met. The characters can both be human, but there can still be magic in the fanfic.

Find fanfics