Stella had informed herself about the Form Laws in the Purist Sect. After all, the Purist Sect specialized in this category of Laws.
So, how exactly did Form Laws work?
Well, one would comprehend different element-specific Battle Laws. Then, one would throw away all the element-specific attributes of the Battle Law, leaving behind only a small portion of the Law.
After comprehending at least three different element-specific Battle Laws, one could fuse the element-neutral parts of the Battle Laws together into a Form Law of the same level.
For example, when one comprehended the level five Laws of Storm Cutting, Fire Cutting, and Frost Cutting, one could take the element-neutral aspects of these Laws and combine them into the level five Form Law of the Sword.
If one paid attention, one would immediately notice why not many Cultivators outside the Purist Sect would practice these Laws.
It was simply way too inefficient.