Predator: Andrew Vachss wrote a story where a Predator targeted serial murderers.Venom, the Lethal Protector, from Spider-Man.The Scourge of the Underworld is an entire organization of these though only a scant handful of its victims are actual killers.The Punisher hunts and kills as many criminals as he can.Night Raven, from Marvel UK (though his stories take place mostly in the US), has targeted serial murderers, including an unauthorized successor to his mantle, Howard Bates, who had admired Night Raven as a child.For a time, Morbius would only drink the blood of criminals.Samhain doesn't see the difference between her and any other slasher, a sentiment Cassie really doesn't appreciate. In one of the later comics, she's even referred to by a talk radio host as the "SKK". Hack/Slash: Cassie Hack is a former Final Girl who becomes a slasher-hunter.This isnt so much because of any moral judgement, as Shiva doesn't really care about such things, but simply because they provide the most challenge to kill. Lady Shiva is a vicious Blood Knight who revels in death and chaos, but most of her victims are other assassins.He explicitly muses at one point that the inmates of Blackgate Prison are mostly only in for theft or less and don't deserve his kind of death. In the Batman Vampire trilogy, Crimson Mist the third volume in the trilogy basically turns Batman into this after he succumbs to his thirst for blood, only just able to control his new urges by focusing only on killing his homicidal enemies who are themselves killers.Regular Batman spends his life fearing that he may become this if he ever loses control. Murciélago: Kuroko has murdered 725 people, and the only reason she hasn't been given the death sentence is so she can kill other mass murderers.William of Moriarty the Patriot targets abusers who are largely immune from the formal legal system, but most often his victims are serial killers.He has also talked other serial killers into suicide while at the prison as well. ID: Invaded: Akihito Narihisago is in Kura Prison because he shot the Challenger, who was a serial killer.(Well, that and the one where the antagonist has Mind Control to stop Shiki from attacking him )
This is part of the reason why the part of the story where they fight is the only one where both antagonists get out okay, more or less. The Garden of Sinners: Both Shiki and Fujino.Eden of the East: Diana, Selacao number 11 hunts rapists and dispatches them by castration via cigar cutter.True to the series' penchant of showing what happens to He Who Fights Monsters, a good number of the Kiras Jump Off the Slippery Slope into Knight Templar (such as Light himself) or just plain Ax-Crazy (such as Mikami) territory. Most notably, the main character Light is a mix of Knight Templar and A God Am I, believing that he will become the "god of the new world" by completely eradicating the world's criminals. Death Note: Almost all incarnations of Kira fall under this trope, with the exception of the one profit-driven Corrupt Corporate Executive.Killer Killer also has Fujigawa, Hijirihara's Childhood Friend who also became this but for the opposite reason, as Takumi enjoyed killing people who deserved it while Fujigawa was a Reluctant Warrior and Well-Intentioned Extremist who wanted to rid the world of violence. Danganronpa: Both Takumi Hijirihara/ Killer Killer and Sparkling Justice (who are hinted, but not confirmed to be the same person) exclusively kill criminals.
Some of the Code Breakers recognize that they are evil themselves, though. He even saves the comic relief from certain death.
In its main plot aboard the Flying Pussyfoot, Vino actually can be considered the most heroic of those involved, as his brutal murder spree only involves the cultists and gangsters who were trying to harm the passengers. However, he takes pride in only killing other criminals, and refuses to do jobs on people who are not guilty. Baccano!: Vino is an incredibly violent assassin, and generally prefers to kill by smashing his targets' faces into the ground from a moving train.She will technically kill anyone she feels like, which includes her boyfriend. Ana Satsujin: Rio mainly kills criminals, though she hates police and makes an exception for them.hack: Haseo, nicknamed "Terror of Death" due to his insistence on killing PKers (which makes him a PKer-Ker).