The Crescent Moon Blades belongs to the Cleansing Incense Ancient Sect. It was given to Li Qiye on his request and he trained with them to use the Invisible Dual Blades technique.
Li Qiye used the Crescent Moon Blades to kill Du Yuanguang and Xu Hui.
The Crescent Moon Blades are Immortal Emperor Min Ren's old blades which he used throughout his life and later became a Emperor's Possessions.
Later Li Qiye used up all the Immortal Emperor power within they became normal blades.[?]
The Crescent Moon Blades is a dual wielding weapon, of Mortal Grade, so it is considered unfit for Cultivators.
Links 5 Appearance(s) of Crescent Moon Blades