Canon

Fluff supported by the creators. It should be noted that canon ≠ cannon, no matter how frequently it is used as such.

Canon itself can be sometimes unclear or subject to change, especially in works which have more than one author (Doctor Who being a notorious example) and works which have gone through more than one version. The latter can be often seen in changes that occur between editions of a roleplaying game; for example in 3rd edition D&D the transformation of a Drow into the monstrous Drider was a punishment, in 4th edition it is a blessing the goddess bestows on the best of the society.

The accursed nemesis of many a canon is the infamous C.S. MULTI LAZOR for this pleases him. Worse now is the mutilated dreck that spews from the mouth of Matthew Ward that corrupts all things and changes universes at his beck and call.