After studying it for several months, Li Shuangyan used the Void Imperfection Physique against the members of the Southern Heavenly Kingdom at the entrance of the Evil Infested Ridge. During her stay in the Ridge she vastly improved her Void Imperfection Physique.
The Void Imperfection Physique enables the cultivator to be stainless and it can't be touched by dao.
Almost all Merit Laws would be ineffective aganist the Void Imperfection Physique. Offensive techniques wouldn’t be able to hurt a cultivator with this Physique and defensive techniques wouldn’t be able to stop it.