The materials used to make the azure arrows came from the ancient battlefield and were imbued with strong killing intent, as well as coalesced grievances of the beings killed in the battlefield.
All of it proved devastating to living beings and common folk would not be able to even search the ancient battlefield, as they would be damaged by all the negative energies permeating the place.
Saleen designed dozens of types of arrows for both Qin and Eleanor and the azure arrow was but one of dozens. As the number of arrow types crafted grew, he developed a greater understanding of the myriad of skills employed by archers.
Alchemy did more than just enabling alchemists to craft equipment for other professionals. It also enabled mages to learn of how energy of different kinds worked in the world. Mages would not have usually encountered a lot of the knowledge.
