The advantage of Heartfire lies in its complete control.
A cultivator doesn't need much knowledge of the Fire Realm or cultivation techniques to have full control over Heartfire naturally.
He can make the most meticulous fine-tuning, keeping every bit of the Heartfire's heat under his reign.
Such Heartfire is naturally suited for Alchemy and Artifact Refining!
Because of this innate talent, Gongsun Yan chose Artifact Refining from the Cultivation Hundred Skills. Also, due to this talent, he chose to affiliate with the Lin Family—he needed Thunderstruck Wood, Spring Thunder, to mitigate the drawbacks of Heartfire.
The more often Heartfire is used, and the longer it is used, the more it can disrupt the balance of the Five Elements within the human body, easily causing imbalance and various ailments.
Therefore, the inhuman appearance of Gongsun Yan, with bronze skin and dark golden muscles and bones, are all changes made out of necessity.
