I've read a novel before, but I don't remember what the name is. It's probably about the male protagonist being a wolf in his previous life, the female protagonist being a sloth, and the male protagonist being raped by the female protagonist in order to eat her flesh.

I'm not sure what the novel you're referring to is. However, I can tell you about a famous novel whose plot is similar to what you described. It's called " The Full-time Hunter." 'The Full-time Hunter' was a Japanese novel by Yoshihiro Tomiken. The novel told the story of the protagonist, Yoshihiro Tomiken, who was a full-time hunter. He transmigrated to a different world and became a wolf. He had some interesting adventures with a sloth. In this alternate world, there is a mysterious biological chain between wolves and sloths, and the protagonist, Yoshihiro Tokugaki, began his adventure in order to break this biological chain. I hope you will be interested in this novel!