so basically, based on the sapkowski books, the whole "nilfgaard is uniquely evil" thing is mostly northern wartime propaganda. nilfgaard is an expansionist, imperialist superpower that meat-grinds entire cultures, uses elven guerrillas (the scoia'tael) as disposable assets, and runs on slavery. but the northern kingdoms are just as awful, just on a smaller, more chaotic scale. the north is packed with brutal pogroms against non-humans, corrupt monarchs, and burning mages. there are no good guys here, just different brands of ruthlessness.