The Unaware Atelier Meister

Original title: 勘違いの工房主～英雄パーティの元雑用係が、実は戦闘以外がSSSランクだったというよくある話～

Kurt Rockhans is a kind-hearted errand boy for a hero’s party, the Flaming Dragon Fang. One day, he's banished from the party and finds out he has the lowest rank in combat. In order to make a living, Kurt picks up various jobs and discovers he has astonishing abilities. Though he doesn't realize it yet, Kurt has SSS-rank skills in anything other than fighting, as he sets off on a new journey.