Disclaimer: I will not focus on Art or grammar, unless the latter would make the deck too difficult to understand.

You know, the operating systems symbols definitely hid a really cool idea here with Argus Umber, once you check the link. Kinda sad it runs into the problem of "max 2 pages per entry".

First things first, I absolutely love the idea and the eldritch horrors involved. The poor guy needs a hug. Mechanics-wise too, the Duel is bound to be an interesting one with the deck, and I have to give Kudos for working the idea into reality, and just straight out coming up with alternative win condition!

I also have to ask for clarification, if the intention is to play both The Maw and then Carna as Plans to Win?

For a bit of criticism, it might be a good idea to explain what {Spelljammer} and other keywords do, since they're not in the main books, and it's highly dependent on table if people know about the fanmade keywords or specific card games? For a bit bigger thing, I think the Maw-mechanics could probably be formatted a bit more clearly - I admit I had some trouble keeping the thread together as things went on. I don't wanna base my thoughts on appearance, but with complicated effects, their formatting helps a lot with understanding what's going on.

Good job!

I'm gonna be real, I think this is a super cool idea. An NPC that basically adds a stage hazard is really unique and cool. Absolutely use this. Great job :)