I'm not sure specifically what 'mercy novel' is about as it could be a very specific or self - named novel. It might be a story that focuses on themes of mercy, perhaps about characters showing mercy in difficult situations or a world where mercy is scarce.
I'm not sure specifically which 'no mercy novel' you are referring to. There could be many novels with that title or a similar name. It might be about a story where the characters face a harsh and unforgiving situation, perhaps in a dystopian world or a cut - throat competition scenario.
I'm sorry, but without more information, I can't determine the author of the 'no mercy novel'. There are so many novels out there and this name alone doesn't give enough clues to identify the author.