An instigator is a criminal who deliberately instigates another person to commit a crime. Its outstanding feature is that he does not commit the crime personally, but deliberately instigates another person to commit a crime and decides to commit the crime.
Zheng was ill and asked Lu to be a ghost town. Lu said nonsense that there was a problem with a certain graveyard. So Zheng nailed an iron rod to the grave under the guidance of Lu, and was later pulled out by the grave owner. Zheng was sick again and suspected that the grave was at work again, so he decided to kill the grave owner to eliminate the disaster for himself. So Zheng tricked the grave owner to the grave and killed him with a kitchen knife is an instigator according to the above definition.