There were many Alchemists who possessed an Anomalous Fire, but those with a High-Level Anomalous Fire were exceedingly rare. Take the Immortal Fire, for example. Even Clan Leader Su Kaifeng had never encountered an Alchemist who wielded it. This was the first time he had ever laid eyes on such a person.
Some who possessed a powerful Anomalous Fire weren't necessarily skilled in Alchemy. They could be Artifact Refiners, or perhaps they simply used their flame to kill enemies. It had no other application.
Yi Tianyun had claimed he could perform Alchemy, and now he had revealed not only an astonishing Alchemy Furnace but also the incredible Immortal Fire. Because of this, many people were already half-convinced of his claim to be an Alchemy Grandmaster.
With such incredible power on display, how could they not be at least partially convinced? The real test, however, would be his Alchemy Technique. They would have to see how he actually refined the pill.
