"Any card—so long as it exists—has a power that is needed."

iyliss:

Omgg thank you so much for asking!! I already talked a bit about cthulhu mythos and gx (you may find about inspirations of arcana forces that doesn’t have much meta, about the world and the devil that are more focus on anime interpretations and that very scary looking reply about judai being randolph carter). But I can sure develop about season 2, and GX in general, since this was about more specific points.
I’ll try to keep it decently readable, Im sorry if i get carried away ^^ Also I hope I don’t make too many mistakes, I’ve red most of the stories I will refer too, but not all, and a part comes from other sources so it might not be exact (and I might reconsider some aspects as I keep reading).
Also I will avoid repeating things I said in the 3 posts linked up there.

First of, why would Gx and s2 more specifically be related specifically to the Cthulhu Mythos, amongst other inspirations? Beside the arcana forces being quite obvious references, there are some narratives, aesthetics and themes in common. Amongst other things:

• An entity from outer space partially coming to earth and leadingit to it’s destruction
• The mix of weird sci-fi (aliens, space, white holes…) and occultism (tarot, spirits, ghosts…)
• A sect. A whole sect right there.
• A general mystery of some aspects of the universe (what is the light of destruction? What is the extent of it’s power, and influence? Where does it and gentle darkness come from?)
• About “knowing too much” (mostly Saiou knowing the future, but you can see a bit of it in Judai’s evolution)
• And so many aspects of Saiou but it’s harder to explain it all

I think that even without having red anycosmic horror litterature, the villain being the leader of a sect that try to destroy the world in honnor of an out of space (and reality) super-powerful entity screams lovecraft.
Ill try talking about other points down there that are less obvious.

In a way, the “main” characters of s2 (judai, edo, kenzan and saiou) follows lovecraftian main characters archetypes.
Judai ressembles characters such as, well, Randolph Carter, and Charles D Ward. Innocent, a bit naive and immature, generally nice though lacking some sense of consequences. There’s often this kid who doesn’t actively try to get involved in things, but have some strong relationship with occult things and will get in all kind of trouble that never really ends well.
Edo… is more about how he loves litterature, doesn’t have much friends, has a (black) cat, drink tea and is american but more about European style. That sounds stupid but it’s also an important part of lovecraftian imagery.
Kenzan is interesting cuz he’s an paleontologist (at least of passion), but in a very stupid way. That may be an unwilling coincidences but I swear the number of incredibly unprofessional (and unrealistic) field rescearcher/archeologist there are in those stories…
And Saiou… There’s this underlying theme (fueled by lovecraft’s racism tbh) about beings/people that are weird, monstruous, different (=not white american protestant men for him), and they probably know some secret dangerous occult magic that will destroy the world, because that is obviously what they want. And that’s pretty much how Saiou was treated. But, what makes those stories more interesting than simple racist metaphores is that said « monsters » are never shown actively doing anything bad (the dunwich horror mostly, and the shadow over innsmouth are especially interesting. In the first, it actually makes more sense than our main monster Wilbur Whateley actually tries to save the world). Which well also goes with Saiou’s story.

And it’s actually hard to explain deeply because I am often scared to associate scenes and aspects that are just a bit alike. But if i have to develop on some specific lovecraft stories, beside The dream quest of the unknown Kadath for s3 and Through the gate of the silver key for s4… In s2 some aspects reminds me of The repairer of reputation (old, very close friend of a good man have been slowly becoming the leader of a cult that does quite shady things and want the return of an old god, while maintaining a good face to his friend who noticed nothing despite everyone else thinking he’s strange), the dunwich horror (Boy hated by everyone deals all alone with an incredibly powerful entity that only brings destruction, ambiguously helping or stoping it, until at the very end the other characters finally realizes that they have to stop it too), at the mountain of madness (Hero with an affinity for spiritual things discover aliens are a thing, but they’re actually nice. But there’s also something evil those aliens tried to fight and failed, and now it’s after the humans), or The case of Charles Dexter Ward (Well meaning boy brings back his very powerful and evil double-from the past- at first tries to deal with him alone, gets all kind of trauma, asks for help as a last resort and no one understands. Notice it works both for the light/Saiou and Haou/Judai).
But for that I actually think it’s more that similar themes (which could be  more likely inspired by typical Cthulhu mythos tropes and stories) leads to similar scenarios than direct references.
However, s2 strongly feels like an incredibly good “adaptation” of cthulhu mythos, especially because it deals a lot more with the dehumanization and trauma that are only implied in the stories. I say adaptation because this universe is actually much more vaste than just H.P. lovecraft (and that’s why I say “cthulhu mythos”, because it’s not just him) and, at this point, is more about the tropes and themes than the characters or creatures.

Also I want to conclude with insisting that, while the extend of lovecraftian inspiration in S2 is debatable, it’s clear that there’s at least one person behind ygo who has a very good knowledge of cthulhu mythos, and has it as a strong inspiration. Not only in GX, but also in the tcg (outer gods), in zexal (i personnaly have some thoughts about don thousand being based of Nyarlathotep) and in Vrains (tindangles being Tindalos Hounds).