It's interesting that there's a form of manga exemplified by Lone Wolf and Cub and Golgo 13 that are about abssolute bastards. Vicious soulless, charmless killers.
However, these characters are also mercenaries and the stories generally revolve around them killing even worse people. In truth, the narratives are often studies in evil that end in blood baths.
That's not a story structure you get in the West. Western authors instinctively explain or contextualise.