I know it's very interesting. Here's a question you think IGA is a full metal alchemist fan? I hear that's popular in japan.
Maybe he's a FMA fan, but I think he's also just facsinated with the concept fo alchemy, plot-wise. I recall him mentioning Enochian language in regards to Bloodstain's plot, and know it's connected to John Dee(whom I referenced in earlier posts regarding historical figures they could reference in this game), whom with the help of his assistant, deciphered the "Angelic Language" and used it for angel conjuring. And another name I brought up, Aleister Crowley, would use some of Dee's teachings in his own rituals. It goes side-by-side with the Ars Goetia and demon summoning. The crystals(both in Bloodstained and of the Innocent Devils in CoD), the Philosopher's Stone(a fabeled alchemic relic) and the Crimson Stone(of CV), it's all very interesting and you can see the connections in concept. It's all pretty cool. The one artwork of the alchemy lab for Bloodstained seemst to have demons being created in glass tubes, which almost reminds me of that Curse of Darkness Kojima artwork: