George R.R Martin was the pioneer behind a new wave of fantasy books where authors did not glorify the medieval setting. On top of depicting life as it really would be, he also writes the best characters out of any fantasy author, even Sanderson. He is the ONLY, and I mean ONLY, author to write truly gray characters. He realizes that good and bad is a spectrum, that they are subjective, that good people can commit bad acts, that bad people can commit good acts, etc. He is the author that most successfully breaks away from the "good vs. evil" overarching narrative that has plagued popular culture, and in doing so perfectly averts the gross oversimplification of human existence.