ersatzinsomnia reminds me of something I think I'd tended to forget, discussed in more detail in
this post and excerpted here:
Thus we have the entire official record of Hastur… tangential, incomplete mentions in six stories passed along a chain of four authors.
All of which highlights the essential mystery and charm of what is commonly referred to as the “Cthulhu Mythos.” The beings of the mythos, the objects associated with them, and their essential nature is not only unexplained, they are un-detailed to such a fabulous extent that all that really exists about them is an atmosphere, a lingering malaise associated with the idea of the beings... a flavor of musty tomes, forgotten secrets, and madness incarnate, brought forth in a whisper. Contrary to the bumper-sticker humor most Lovecraftian fans banter about, Hastur is not an ancient god from beyond time and space who comes whence thrice spoken is his name... you’re thinking of Bloody Mary. Hastur is indefinable.
I'm especially prone to nailing down things. And it's good, sometimes, to be reminded of how vague they actually are; that between Chambers and Lovecraft, you can't even tell if Hastur is a person, place, or thing.
(Not, you know, that the King in Yellow doesn't still get me all starry-eyed, and that I don't have definite impressions of Carcosa. Just that they're not universal ones.)