Satire at a good man who is not firm. The saying that the dragon slayer will eventually become a dragon comes from Nietzsche's The Other Side of Good and Evil, which means that the warrior who kills the dragon will eventually become another dragon. The connotation expressed in this sentence is that the dragon slayer originally represented the just side, and fought against the dragon in order to destroy the dragon for mankind, with the aim of ending the battle by fighting, but in essence there is no absolute justice and evil in this matter, because the battle itself is full of unhappiness. This sentence is generally used to satirize some good people who are not firm. On the contrary, people who fight against the black forces are most likely to become black and evil forces because they often fight against the black forces.