In order to create it, Dark Crow brought Min Ren to the most dangerous of the Forbidden Grounds, and they saw ten suns floating up and down, reenacting a grand Dao. After this scene, Min Ren was able to create the Violet Yang Ten Suns Merit Law, while Dark Crow gave him many advices, and helped him to perfect this merit law several times over.
During Destruction of Cleansing Incense Ancient Kingdom the Sect lost many of its Merit Laws. The Violet Yang Ten Suns Merit Law wasn't completely lost, but seriously damaged. Many important parts of it were flawed, so no one dared to cultivate it ever since.
Elder Wu cultivated the Violet Cloud Merit Law, because it was very suitable for him. He researched the Violet Yang Ten Suns Merit Law for a long time, but eventually he realized that it was too damaged, and he wouldn't be able to cultivate it. He had no choice but to give up and cultivate another Merit Law.
After learning that Nan Huairen and Protector Mo are both cultivating the Violet Cloud Merit Law, Li Qiye had promised to them that within a year they would be able to practice a complete Violet Yang Ten Suns Merit Law.
Around eight months later Li Qiye regained his memories about the Violet Yang Ten Suns Merit Law and brought the complete manual for it to the Sect's Elders. As a reward for his great merits, Li Qiye asked the Elders to allow Protector Mo and Nan Huairen to learn the Violet Yang Ten Suns Merit Law and the Elders agreed.