Cthulhu Mythos Canon

 I've been researching Cthulhu and before I release the blog, there is something that needs to be explained, that being the canonicity of the Cthulhu Mythos. The Cthulhu Mythos is a shared universe where multiple writers write in, like the Marvel or DC Universes. Unlike those however the is no official canon to the Lovecraft Mythos. Everything Lovecraft wrote is public domain and he encouraged other writers to incorporate elements of his writing into theirs. In a sense everything is canon to the Lovecraft Mythos. This makes things rather confusing and inconsistent however there is some thematic point to that, as Lovecraft's writings hold a strong theme of mankind's inability to comprehend everything, the theme of neccesarily limits in perspective. Contradictions create an authenticity to madness as logic is coherent and consistent while madness is not. However it makes knowing what to include in a vs debate a bit harder then normal. For simplicity's sake, the Cthulhu Mythos wiki has created a tier system of canonicity that I am following in my blog that should be released alongside this one. This blog is basically just to explain what each tier. These I call "Cycles" as in Myth Cycle, a commonly used term to refer to a set of collected stories within the Mythos.

Tier 1: Lovecraft Mythos

The highest tier of canonicity is Lovecraft's own stories. Obviously these are canon. They are canon by definition of the word canon.

Tier 2: Original Mythos

Lovecraft had a circle of writer friends who would reference his writings in theirs, and he would reference their writings in his, giving them inclusions his personal approval. Elements from the mythos almost universally accepted as canon like the Hounds of Tindalos are here because they were written by one of Lovecraft's friends during his lifetime which he approved of, generally by referencing in his own writing. Some also place secondary writings by Lovecraft here, such as his letters which sometimes contain mythos information, basically to say they use them so long as they do not contradict his writings. Almost everyone considers these canon. You can find a few sticklers that demand only Lovecraft's own writing but this is very fair to use.

Tier 3: Derleth Mythos

This tier includes the writings that Lovecraft's circle wrote after Lovecraft's death, in particular the writings of August Derleth. Derleth's writing is heavily contentious in the Mythos fandom due to what many see as a wild divergence from Lovecraft's intent in writing the mythos, by making it adhere to a human system of morality and associating it with the 4 elements. Whether things at this tier are canon is highly contentious.

Tier 4: Expanded Universe Mythos

This includes all works that are intended to be set in the Cthulhu Mythos universe. Obviously by that description it is vastly larger then the prior tier and contains published and unpublished works, making it technically impossible to ever fully analyze, not least because stories can directly contradict each other. This is generally not considered canon, except in so much as the stories are canon to each other and form micro-mythos universes that draw from any number of elements from the prior 3 tiers. 

Tier 5: Greater Mythos

Includes all depictions of Mythos elements, regardless of the source. For vs purposes this is essentially a composite version of the characters. Thie tier treats the characters more as metafictional constructs with all physical to conceptual perspectives on the characters as being aspects. Similar to previous category, it is impossible to fully analyze. This tier is obviously not canon save for any the perspective mentioned above, as the series are so contradictory in every regard due to being any possible imagining of the character that it can not be reconciled.