Usually, for one to be an alchemist or refiner, one had to cultivate the fire Qi attribute. This is because to refine or concoct pills or potions, the materials had to be burned with fire to give a desirable result. Apart from the mystical ways martial artists used to refine their weapons or concoct their pills, a mortal, for instance, a blacksmith has to heat the furnace to an unbelievably high degree to melt the many precious stones and metals to form a sword. This same ideology applies to the refiners and alchemists of the martial world.
However, Nero wasn't that type of martial artist. At some point in his life, he pursued the path of alchemy, surprisingly devoting his time to it. Until he encountered a bottleneck because he didn't cultivate the fire Qi attribute. But even at that, there were some auxiliary techniques one could learn to help them concoct potions and pills if they didn't cultivate the fire Qi attribute.
