Even if it were true that a non-relative could be the one granting permission, the things you're implying, whether that be rape or kidnapping, would likely both still be crimes.
As dark at it is, it should also be known that many countries have no specific, outright law against cannibalism or beastiality, such as specific terms in things like penal codes, but those acts are often covered by other statutes, like murder, desecrating cropses, animal cruelty, etc.
No worries. lol and Azhurie is likely from Japan, so you can easily look up Japanese law if you wanted to check for yourself. They actually have a 'murder with consent' charge in their penal code, which is bizarrely interesting.
Also, cannibalism and murder are not related. You can go to a surgical center, consent to an amputation for cosmetic purposes, take the removed flesh, and give it to someone else for them to eat, without breaking a single law.