Chaka from Black Lagoon is possibly the biggest Jerkass in the entire series with little to no excuse for his needlessly sadistic and often idiotic behavior. Even Sociopathic Heroes such as Revy and Ginji are disgusted by this asshole's actions, and his abuse of Yukio at the bowling alley in particular is enough to bring out Rock's absolute worst language and drive him to violence. He gets a well-deserved comeuppance at the hands of Ginji, who uses his shirasaya blade to slice up Chaka's gun — and then cut off his hands. Followed by forced drowning.
This actually managed to be subverted with Hänsel and Gretel. Yes, they are irredeemably Ax Crazy, mass-murdering childrenFor the Evulz, but the sheer, insane HELL that they grew up in would screw anyone up. It is made clear that they are not the true Complete Monsters; rather, the realComplete Monsters are the people that made them into what they are. Good thing one of the siblings' first atrocities was butchering a good number of them. Also, they have loyalty to each other and at least one of them states that "I feel a little bad." about killing 2 other orphans and using them as decoys, making them non-qualifiers regardless of what their Freudian Excuse makes people think about them.