WARNING: Game of Thrones finale spoilers below!

George R.R. Martin s book series A Song of Ice and Fire may have inspired the biggest TV show in the world, Game of Thrones, whose finale aired Sunday to mixed reviews.

But in a Monday night blog post, the author told readers to expect quite a few differences when the lengthy final two installments in his series of epic fantasy novels finally hit bookshelves.

I am working in a very different medium than David and Dan, never forget. They had six hours for this final season, Martin wrote , referring to the HBO series showrunners, David Benioff and D.B. Weiss.

Martin said his final two books, titled The Winds of Winter and A Dream of Spring, will fill 3,000 manuscript pages between them, and if more scenes are required to complete the story, Ill add them.

Martin explained:

There are characters who never made it onto the screen at all, and others who died in the show but still live in the books so if nothing else, the readers will learn what happened to Jeyne Poole, Lady Stoneheart, Penny and her pig, Skahaz Shavepate, Arianne Martell, Darkstar, Victarion Greyjoy, Ser Garlan the Gallant, Aegon VI, and a myriad of other characters both great and small that viewers of the show never had the chance to meet. And yes, there will be unicorns of a sort

Some things will be the same, though. Asking himself whether the HBO ending will be the same or different than his books, Martin rambled: Well yes. And no. And yes. And no. And yes. And no. And yes.

How about this? Ill write it. You read it, he proposed. Then everyone can make up their own mind, and argue about it on the internet.

Martins bountiful source material provided Game of Thrones showrunners Benioff and Weiss fuel for five hit seasons, but that well ran dry in Season 6 . The showrunners said Martin informed them of major plot developments contained in the last two novels, but were forced to look within themselves to come up with dialogue, lesser plot points and other loose ends for Season 7 and Season 8, along with much of Season 6.

While previous seasons contained 10 episodes, Season 7 contained only seven, and Season 8 just six although the episodes were typically longer than usual, packed with battle scenes and dragon fire.

Many fans complained that the final seasons didnt allow sufficient time to explain the major plot turns that led to the shocking finale : Daenerys (Emilia Clarke) burning down the Westerosi capital of Kings Landing, and Jon Snow (Kit Harington) stabbing her in the heart to prevent further bloodshed, leading to Bran Stark (Isaac Hempstead Wright) being named king while Jon rejoined the Nights Watch which still, for some reason, exists.

Martin offered no criticism of the show. Instead, he praised the writers, cast and crew who had devoted so much time creating eight epic seasons.

We had some amazing people working on this show, as all those Emmys bear witness, Martin wrote.

Its not quite the end of Westeros, either. As Martin recently revealed, three Game of Thrones prequels are still in the works , with at least one of them destined to make it to our screens if all goes according to plan.