how can it be fanfic if Keyes, the official writer of the official, up to date lore looked at it and used it in the book? MK is more like Lovecraft if he suddenly decided to go write romance novels instead, and came back once in a while to work on his old mythos wile Derleth was working on them too.
Attrebus, since youre reading the topic: what is your first hand view of the landfall?
I like MK's writing, but the official line has always been "If it's not in the games, then it's not official lore". I'm sure that extends to official books as well, so the Infernal City version is more official than the MK love letter.
From the sounds of it, MK knows the path that has been mapped out, and probably helped define the future direction. However, what he helped define might not be what Bethesda is going to use. (I don't know how much contact MK and Bethesda have in regards to the future direction of The Elder Scrolls world, so I can't really comment).