After opening Jenny's task line, Elvis Presley will say that he has something for you, too. Go to the Wizard Tower in Service, and start the task by talking to him on the first floor. Service will give us a bottle of potions, and then give it to an NPC man named Neferili. According to the progress of the Neferi mission line, Neferi will appear in three different positions. Whether to give the medicine to nephilim will directly determine the outcome of nephilim. If the potion is given to Neferili, Neferili will become Service's puppet, almost equal to death. If you don't want to give the potion to Neferili and want to advance the Servis mission line, you can go back to the dialogue between Dafu and Jazz White and select the option of "Show Servis' potion". Sir White will accept the potion, and please tell Severus Neferi that he has already drunk it.