テガミバチ

Lag Seeing, a young boy in the sunless land of Amberground, is discovered as a "letter" by Gauche Suede, a skilled Letter Bee tasked with delivering precious messages. After being safely delivered to his destination, Lag is inspired by Gauche’s dedication and resolves to become a Letter Bee himself. Years later, Lag sets out for the capital to take the entrance exam, accompanied by Niche, a mysterious girl with extraordinary abilities who becomes his "Dingo" partner. Together, they face dangerous creatures called Gaichuu that threaten their deliveries across treacherous landscapes. Lag’s journey begins with heartfelt letters and the hope of reuniting with Gauche, who has mysteriously disappeared. (Unreviewed summary by Grok 3)