The Unaware Atelier Meister

One day, Kurt, a kind-hearted boy, is suddenly kicked out of the Hero's Party for being "useless." He finds that his aptitude for weapons, magic, and all other combat-related skills is the lowest rank, so he takes odd jobs repairing the castle walls and digging for minerals to make a living, where his exceptional abilities are immediately revealed. He proves to be skillful in cooking, building, mining, and crafting magical tools--in fact, his aptitude for every skill unrelated to combat had an SSS-ranking. Kurt, however, seems completely unaware of his talent and ends up saving people, the town, and even the country through his unaware actions. <em class=de-emphasized>(from manga)</em>

Synopsis from Anime News Network