"Fire represented heat.
The Fire Control Dao primarily focused on controlling the temperature of flames to melt materials and refine into spirit pills.
However, no matter how the temperature was controlled, fire remained fire; it couldn't possibly condense into ice.
Yet, there were many materials in alchemy that could only exert their effects in environments of extreme cold.
Like Three-Colored Profound Ice, Primordial Heavy Water, Cold Heart Grass, and so on.
Many materials even required extremely low temperatures during the melting process, to preserve their spirituality and greatly increase their activity.
Just like the Awakening Pill you all refined earlier, during the fusion of Burial Moon Flower, Lonely God Grass, Hundred Spirits Fruit, and other materials, the temperature needed to be maintained at a point where water would freeze to achieve the best results.
That was why ice flames were needed in alchemy.
