Based on the flames used, alchemists are classified into Inner Fire Alchemists, Exotic Fire Alchemists, Heavenly Fire Alchemists, and Divine Fire Alchemists.
An Inner Fire Alchemist is one who uses their inherent fire attribute, transforming their spiritual power into flames within the body.
Exotic Fire Alchemists capture the Exotic Fire naturally spawned on the mainland and make it their own. After a period of natural assimilation and testing, and the absorption of spiritual energy from heaven and earth, the effectiveness and power of the Exotic Fire far surpass that of their inherent fire attribute. If the existence of alchemists is as rare as phoenix feathers and unicorn horns, then the existence of Exotic Fire could only be considered a speck of dust on those feathers and horns.