The Eight-Nine Mystical Arts were certainly not created by Luo Lie.

From that drop of ruby blood, Luo Lie had already learned that it was created by East Emperor Taiyi, who intended to use the Eight-Nine Mystical Arts as a foundation to create his own Saint-level technique.

Luo Lie merely took it out and gifted it to Yang Jian.

But others didn't know that; they thought he was so extraordinary that he could casually create techniques that shook the world.