The real reason

"He wants to seize the sword core condensed by his master!" the old man explained the reason.
"Seize the sword core? It seems to be of no use to him, right? Besides, even if he needs the sword core and the sword core, he can take them from other sword cultivators. Why does he have to kill his own brothers?"Hiram Irwin didn't understand.
"No, according to what we learned last time, that bastard Xiao Chi has obtained an evil method that requires the use of the same sword core and knife core...