While people think battles between tier High 1-As are completely inconclusive, I'll say the Nameless Mist takes this rather easily.
Do you guys remember the reason why Yog was changed to High 1-A?
Azathoth the Abyssal Idiot said:
I know I'm running this topic into the frickin' ground, but I kinda feel like we should upgrade Yog to High 1-A, as he's one of the very few Outer Gods directly compared to others in the Mythos. In Lovecraft's original "pantheon", if one can even call it that, Yog was considered to be equals with Azathoth in importance. This is not to say he's as powerful, as Yog is still part of Azathoth's dreams, but Yog is everything in his dreams. All that is, was, and shall be is embodied in Yog-Sothoth, and all is a part of him. This doesn't exclude the other Outer Gods either, as even amongst them, he is the Supreme Archetype, meaning there are quite literally a countless number of other 1-A beings living inside of Yog. There's a reason that there are only three main branches descending from Azathoth on Lovecraft's family tree. Shub-Niggurath and Nyarlathotep are considered the only two gods not a part of Yog, and even this is debatable.
Not to mention that Nyarlathotep, who is considered to be the weakest of the full Outer Gods, is already well within the 1-A category. Shub and the others are unfathomably beyond him, and Yog is unfathomably beyond all of them. Hell, in Through the Gates of the Silver Key, he even makes Randolph Carter omniscient and gives him the abilities of an Outer God, because as Carter learns from the experience, all beings, regardless of how low or high on the dimensional scale they are, or even if the are boundlessly beyond it, are merely infinitely small aspects of Yog, who is the Supreme Archetype. I say this not as some kind of Cthulhu fanboy, but because I can genuinely not see what about this doesn't make Yog High 1-A.
tl;dr
To call Yog "just" 1-A is a serious lowball, in my honest opinion.
The Nameless Mist is untouchable even by the Outer Gods, and created Yog-Sothoth without even trying to do so. From what I heard, EGD practically stalemated DMB Yog, and the Mist > Yog, so the Mist so win rather easily. Even with Athleta Aeternum, EGD can only summon 1-A alt Demonbanes at best, or infinite-dimensional Demonbanes with dimensionless magic, all of which would be useless against the Mist. I also doubt the Shining Trapezohedron will work on Mist. EGD with the Shining Trapezohedron defeated and sealed the Court of Azathoth barring Yog-Sothoth and Azathoth. If the ST couldn't work on Yog its definitely not working on the Mist.
I personally think that High 1-A battles, while difficult to figure out a winner, are quite plausible. It all comes down to scaling or something. EGD = Yog, Mist > Yog, therefore Mist > EGD. While Mist could also probably = Yog, the Mist itself created Yog, so I think Mist > Yog.
