I know nothing about the manga, except that it was written and drawn by a couple Korean guys. Judging by the reactions on the MAL forums, it seemed like the manga fans were pissed, because Sunrise took some liberties in straying from the manga storyline. It’s not surprising. Rarely does the adaption live up to the fan’s expectations based on original source material. Lucky for me, I can just comment on the anime without having to worry about that.