Was he really though? I think one thing this manga has done really well is show us that there are two sides to every issues; every single time Monko has helped a guy for "justice" she often hasn't heard both sides of the story and therefore helps the "wrong person"depending on your view of the issue. In this case, as the townspeople said, there really was no difference between the two gangs. The female leader said the same in that Manji's gang was really no different. Both of the gangs got innocent civilians killed in their crossfire, which was the reason Manji was killed.
He was by no a "great" dude. Let's not forget that he was originally okay with using Monko as bait, which if she was a normal person, would definitely have gotten her killed. So he wasn't perfect imo. don't know if I can blame him though considering you have to have ruthlessness to survive in this world.
IM SO UPSET YAKUZA GUY WAS SO HOT AND PERFECT UGHHHHHH