In this chapter, Banxian explains that he cultivated three elements: earth, metal, and water. He gained the metal element from demon, which made him stronger because metal generated water. In other words, he gained the ability to use fire, water, and wood all at once. He says that he will not allow his son to use the fire and water simultaneously, because he will die if he does. He tells his son that he has already killed him.
In this chapter, Banxian explains that he cultivated three elements: earth, metal, and water. He gained the metal element from demon, which made him stronger because metal generated water. In other words, he gained the ability to use fire, water, and wood all at once. He says that he will not allow his son to use the fire and water simultaneously, because he will die if he does. He tells his son that he has already killed him.