The reason why he chose "Xuantian Immortal Sword" as Shen Congwen's cultivation technique was not as simple as Lin Feng had said—that he only had this technique.
In fact, Lin Feng's "Xuantian Immortal Sword" technique naturally came from the hands of Qi Luyi, and the reason Qi Luyi gave this technique to Shen Congwen was precisely because Shen Congwen's character had certain aspects of persistence and fanaticism. These are exactly the essential qualities needed to cultivate the "Xuantian Immortal Sword" technique!
It is known that the "Xuantian Immortal Sword" incorporates some techniques of the sword cultivators. The ancient lineage of sword cultivators emphasizes being "unstoppable and never retreating"!
Even if there were mountains of blades and seas of flames ahead, sword cultivators would not frown nor harbor a thought of retreat!
