I was trying to find evidence of Kim Eun Hee’s original 2015 webtoon (which goes by “The Kingdom of God”) but it seems YLAB has purposefully pulled it to make it available later after some “digital remastering” (which has nothing to do with the Netflix airdate, I’m sure /sarcasm).
However, here are a couple of images that apparently were made available for press releases:
The Obsessive Dilettante 