I do not think he cares much about what is in the games or comics, other than that none of those are canon to his work. Nor am I convinced that CDPR have any obligation to make sure that their story follows events that happen in the books after the beginning of the games' story. But if that was the case, I would rather not see more Witcher games made in the future and prefer CDPR to make their own IP - the risk of large parts of the content in the games becoming invalidated or "overwritten" by the work of a different author (possibly even by books that are written after the games and fill the same holes in the story, which would be a rather unfair situation) is not acceptable in my opinion.
Sapkowski has pretty clearly stated that he doesn't intend to take anything that happens in the games or other extended mediums into account if he ever writes a continuation to the Witcher saga. They're essentially fan sequels to him.
However, the same doesn't seem to hold true the other way around. CDPR's writers have been quite methodical in having pretty much all of the book canon act as the games' backstory as it is. Their work is definitely more than a mere adaptation that takes the characters and setting, but plays fast and loose with everything else. Well, there are some date disrepancies, but other than that, the games are essentially sequels to the books as-is.
So it makes sense they continue that trend even in post-W3 content.
Is it confirmed 100% that there is no possibility of empress Cirilla, even temporarily (for some time between 1273 and 1289) ? If not, then the absence of evidence does not equate to evidence of absence. Anyway, the books do not say it either that Geralt is with Ciri after their ending (regardless of how you interpret the ending), nor that Ciri defeated the White Frost.
There *is* some wiggle room with Ciri being an Empress, since it could be that she didn't ascend to the throne as a sole ruler, but as a wife to Morvran Voorhis, who was Emhyr's successor according to Encyclopaedia Maxima Mundi. In fact, when you talk to Voorhis in Witcher 3, he actually alludes as much.
However, there is something else in the saga that makes Ciri as empress seem unlikely. There's that subplot in the Lady of the Lake, taking place about 200 years after the saga's main events, where two sorceresses, Nimue and Tilly, are trying to put together the pieces of what happened to Ciri in her own time. And they seem completely oblivious to what happened to her after the Rivian pogrom, which is kind of a massive headscratcher if she really became the Empress of Nilfgaard. There's no need for oneiromancy, just open a ploughin' history book, you two!
Of course, even this is not a direct contradiction to Ciri being an empress, because there's a number of hand waves that can be used to explain this one away (like revisionist history writing, which is actually pretty much what EMM is). It seems quite evident however, that Sapkowski never meant for her to be an empress, so the notion that CDPR's writers are simply sticking to the grandmaster's canon in extended mediums is still valid.
Well, guess I have to walk back a bit concerning the contradictions between Sapkowski and CDPR. Apart from the wonky dates I mentioned above, this whole thing with the White Frost is a pretty big one. Nimue and Tilly certainly don't identify it as a space-traveling Eldritch Abomination, but a simple natural ice age that awaits a few thousand years in the future. I know this is bit of a slippery-slope handwaving, but the best way to explain this disrepancy away is to simply presume that *both* are right. Ciri does defeat the being or creature that threatens to freeze the world at that instant, but the ice age still arrives later on, due to, well, whatever it is that causes natural ice ages.
As for Ciri becoming an empress to fulfill the Ithlinne's prophecy, let's keep in mind that a big part of the saga is that people have various interpretations about what that prophecy might mean. Figuring that Ciri needs to become the ruler of the most powerful Empire on the continent is pretty much how Emhyr interprets it. Yet for example Vilgefortz has a completely different (and far more grisly) idea about how to bring the prophecy to fruition. And both are pretty much wrong about it, to be honest. Prophecies are generally pretty figurative. As the Lady of Time and Space, Ciri is, in a way, already the mistress of a realm far bigger than Nilfgaard.
*highfive*
