The biggest problem demons have with writing is that paper dries out very very fast in the Abyss due to the heat and gets brittle
Plus there are random acts of flame throwing, exploding gas balls…in all not a really conducive place for books and parchment.
Now, the advent of m-books, (mirror-books) has helped, but to write in that, you have to use a speech to text spell, so it’s more like dictation than writing.
Antefalken’s writings are done in Astlan.
Actually, the various Exadors have published numerous texts, dissertations and research notes, again in Astlan.
There were writings by Ramses….so when demons write it’s mainly in Astlan or some other plane of man.
The topics are about what you’d expect, sex and violence things going boom. A number of demons have sold scripts to Michael Bay.
Also lots of HBO…well…OK, that and Cinemax After Dark….