I'm So Panicked After Becoming the Great Emperor of Fengdu

Lin Luoyan never imagined that, after enduring treatment over and over, he would transmigrate at the very end of his life into Fengdu Emperor, a character from a book he'd once read who had only one line. Wait, why is he the only one in the entire underworld? There isn't a single ghost here! And the most outrageous thing is that the innate treasure he received after becoming Fengdu Emperor is a book titled Five Years of College Entrance Exams, Three Years of Practice. 1. This is a fictional setting, so please don't scrutinize it too closely. 2. Ahem, this is a modern underworld infrastructure-building story. Theme: The net of Heaven is vast, yet nothing escapes it.