100
The Witcher's Liam Hemsworth hadn't watched Netflix show or read the books before Geralt casting
(www.eurogamer.net)
Witcher books, Witcher games and everything else Witcher.
I don’t think the actor does, but the director and/or production has to. If it’s not similar to the source material just call it something else, but I do get saying “based on XYZ” makes for easier marketing.
Oh absolutely. Production needs to know and understand it. 100%
The atrocity that is Amazon’s Wheel of Time is evidence of this.