On the surface, Kazutaka Muraki is a compassionate physician. However, this is far from his true nature. Performing cruel experiments on human subjects with no remorse, he cares very little about the suffering of others. Muraki is more than your run of the mill mad scientist – he is a sadistic killer. Sometimes characters are just heartless and shallow, with little explanation as to why. However, Muraki is a character with a lot of depth and though his twisted behaviors are explained to a degree he remains extremely cruel, earning him a spot on this list.

Medusa is one of the main antagonists in the series. While witches aren't by nature amoral, Medusa is not only evil, but a formidable foe in battle. Her powers go beyond combat – she also is an incredibly capable and remorseless manipulator. She is another character who enjoys hurting others, and has no qualms about taking any means necessary to achieve her goals. Though at times she feigns empathy, at her core she is a truly wicked and sadistic character, putting her on this list.

Hisoka is force to be feared. He lives his life in a self-indulgent manner, with no regard for others. He does not hesitate to take the lives of people that present themselves as obstacles, but his murderous streak is more complex than being a simple tool to achieve his means. The thing that brings him the greatest pleasure of all is to kill difficult opponents - in the most painful ways that he can. Often times he goes through great lengths to orchestrate these killings, and it is this unadulterated bloodlust that puts him on this list.

Educators are supposed to be figures that students can look up to, but Kiochi Shido isn’t even the type of person you’d want in the same room as children. Teachers shouldn’t encourage bullying, and they certainly shouldn’t use a zombie apocalypse as an excuse to manipulate their students. There are sadistic characters who remain fan favorites, and then there are ones that just make your skin crawl in visceral disgust. Though a relatively minor character, Shido is certainly that special breed of monster, and definitely earns a spot on this list.

Yuno Gasai maintains the illusion of being a perfect girl. She is a model student, smart and beautiful. Under this polished veneer lurks one of the most sadistic yandere characters in anime history. Whenever anything gets in her path she takes it down without hesitation, or remorse. Like the other characters on this list, Yuno has no aversion to violence. A boxcutter is her armament of choice, though she is seen using an array of bladed weapons throughout the series. She is cold, calculating, and utterly ruthless, and receives a mention here.

What would you do if you had the ability to kill anyone anonymously? High school student Light Yagami finds out when he gets the Death Note – a book allowing him to do just that. He chooses to eliminate people he sees as unworthy, claiming to endeavor to make the world a better place. They say power can corrupt, but Light Yagami seems to have a few screws loose from the start of the series. The whole time he assumes the title of a vigilante, but it becomes clear that he enjoys killing people – a little too much. The glee with which he takes lives puts him on this list.

Alucard is a vampire who is bound by contract to work as a mercenary, loyal only to his master Sir Integra Hellsing. His purpose is to act as her protector, no matter what the cost. As events in Hellsing unfold, he is repeatedly placed in combat and demonstrates his capabilities as a super-natural force to be reckoned with. In the ways that only an ancient vampire can be, Alucard is intimately acquainted with bloodshed. Not only is it familiar to him, but it happens to be his favorite past time. He kills vampires in the name of a higher power, but his expressions undeniably showcase his enjoyment and excitement as he does so. Hellsing is full of such characters, but Alucard is the most extreme.