I Entered My Own Novel and Became a Death Mage

[Transmigration + Western Fantasy + Omniscience + Powerful Protagonist + Power-Fantasy Elements + One Female Lead] After finishing his novel, Bai Ye fell asleep with his head on the desk. When he woke up, he had transmigrated to another world. “What? I've ended up inside the world of my own novel?!” Then he happened to meet the novel's white-haired, red-eyed heroine. “She’s beautiful...” Later, for reasons of his own, Bai Ye began studying forbidden arts: decay magic. He also had to outwit all kinds of demons. Shapeshifters lurking everywhere, a mysterious “Prophet,” a powerful Demon King... One dangerous attack after another came his way. But Bai Ye refused to back down. Facing a shapeshifter: “Shapeshifter, you wouldn't want your plan to be forced into motion ahead of schedule, would you?” Facing the “Prophet”: “‘Prophet,’ you wouldn't want me meddling with the threads of fate, would you?” Facing the Demon King: “Demon King, you wouldn't want...” Ahem... In short, Bai Ye fears nothing. Because... “I am the author of this world!” (Note: Felice is not the heroine of this book. She is only the heroine of the novel written by the protagonist. The heroine of this book is the “Prophet.”) (This book currently has several titles. For readers who found it under the title Please Forgive Me, Miss Prophet! :) (That title comes from Chapter 59~) (The heroine may not appear much in the early stages, during the human-demon arc. The male and female leads are on opposing sides then, so they won't spend much time together. Thanks for understanding. After the human-demon arc ends, the heroine will join the protagonist's party.) The synopsis may not do the story justice, so please give the main text a try.