Ain was born into a world where each person's fate is determined by the goddess of light. She determines which professional sphere each individual will belong to. However, the skills for a specific profession are given by the goddess of darkness. Their work is mostly complex, which is why there are no contradictions or inconsistencies. Moreover, professions are mostly determined by time-tested standards, except for occasional need for warriors or mages. In Ain's case, he is destined to become an appraiser, and he doesn't require any special knowledge, except for the ability to wield a magical object.
To some extent, Ain sees this fate as unfortunate because his profession is not in demand. He tries to join a group of adventurers as a warrior, but instead, he is used as a helper. He is even assigned the role of bait for monsters, and when he tries to escape, he ends up in the territory where the world tree Yggdrasil is located. The world tree represents the center of all magic in the world and was previously divided into nine trees that now grow in various places. Ain is ready to help the tree communicate with the spirits of its kin.