Every person has a fetish, no matter how intensely one denies it. But there is a huge difference between falling for nice feet and the risk of being killed. Assassinophilia is a paraphilia of an exploratory type, in which orgasm can be reached by the possibility of one's death by murder. It is often mixed with a desire for sexual suffocation, or for planning their own death. Luckily, this fetish is very rare, but it is very dangerous, since it is hard to find the line when it still gives sexual pleasure, but it does not cause death yet.
It might sound as if the problem was not real, but only a theory, and yet, there are several documented cases of people with assassinophilia, and even deaths that were caused by such sexual acts. And it does not matter whether the final death was consensual or not, the person, who kills his or her partner during sex will be a murderer.
However, there are even more shocking fetishes that can be deadly. Vorarephiles, for instance, are aroused by the thought of eating or being eaten by another person, or watching how it is performed, or in special cases – autosacrophagy – the object of desire is eating one's own body.
In these cases, consent should not be considered legitimate, since being killed for sexual purposes is beyond those limits that even a sexual liberal and an open-minded thinker would accept as a proper sexual behavior. Consent is never an excuse for murder.