In the Magical Domain of frost, light, and darkness that Lin Li had created, the laws of ice was the one that he had truly mastered, and it was also the one that he had based his Magical Domain on. The other two Laws, light and darkness, were only there because he had external aid, and he could only depend on the laws of ice to form the Magical Domain.
As the laws of ice was a secondary Law derived from the water Law, its power was limited as compared to the seven basic Laws. Amongst the three Laws that the frost, light, and darkness Magical Domain was constructed of, the laws of ice could be said to be a short board of the Magical Domain.
However, once he had gotten hold of the Polar Snow, he would be able to use the power it contained to perfect the laws of ice and even transform it into the primary and original form of water elemental Law. Ultimately, he would be able to turn his Frost Domain into a Water Domain.