"Necromancy and spirit enhancement are basically the same thing...." Bai Xiaochun murmured to himself as he looked at the information in the bone slip. From what he was reading, all of the various types of multicolored flame in the Wildlands were produced by necromancers, a fact which caused Bai Xiaochun's heart to leap with excitement.
After generations of experimentation and research, the formulas for everything from one- to fourteen-colored flame had been well-established. In fact, there were multiple variations on how to conjure each of those types of flame.
Such formulas weren't exactly secret within the Wildlands. Although not every necromancer had the skill to use all of the formulas, all of the aristocratic necromancer clans had the formulas in their records.
However, the formula for fifteen-colored flame was a tightly-kept secret that not even mid-level necromancer clans had access to. Only the large clans and other major powers had them.