Is that there is no novel and MC died and went back in time, but his mind was so broken and traumatized, he really did create an alternate personality and believe everything before was fake as a trauma response. Disassociate
Unlikely tho. Most likely is that his friend is the one who wrote the story after they parted (tho why he would write something so violent about someone he likes is another mystery)
Is that there is no novel and MC died and went back in time, but his mind was so broken and traumatized, he really did create an alternate personality and believe everything before was fake as a trauma response. Disassociate