The Immortal-Slaying Flying Blade is a treasure closely associated with Luya Daoren in Investiture of the Gods. Its use involves a gourd, radiance, and a strange being with eyes and brows appearing within the light. This is a distinctive act of deploying a supernatural treasure, rather than simply throwing a small knife by hand.
In chapter 48, white rays hold the opponent while Luya bows and gives his command; the treasure turns and beheads its target. Chapter 70 explicitly names the Flying Blade as Luya takes up the gourd, linking the name, vessel, and wielder.
The procedure and Luya’s composed manner are central to its identity. Its formidable name conveys menace without establishing an unconditional rule of victory: the novel also depicts Luya withdrawing before Kong Xuan’s divine light.