Hailing from Rubon village, Kautsu left seeking work, aware he lacked specialized skills and effectiveness. Rescued from a large slime by Ririetta while returning a lost item, he encountered an armor shop facing severe financial hardship and potential bankruptcy. He joined as a clerk to help stabilize the business. This shop creates and sells functionally effective, revealing armor exclusively for female adventurers—a niche contributing to its precarious finances.

His daily responsibilities encompass shop operations, customer service, and financial management. Kautsu works diligently alongside owner Naaden, the armor designer, and Ririetta, Naaden's daughter and the shop model. Despite initial unfamiliarity with concepts like profit, loss, and common sense—a trait shared with Ririetta—he shows willingness to learn. Regular customers include the powerful swordswoman Frealica (Furearika), who teases him to provoke naive reactions, and the flat-chested sorceress Miina (Miina), who shares Naaden's appreciation for the distinctive armor designs.

Kautsu maintains a significant bond with Mokuku of the Rabitta tribe, a friend from Rubon village who accompanies him; her unique apron symbol signifies their longstanding connection. He also interacts with other figures like the elven soldier Selas (Selas), stationed at a customs checkpoint and maintaining a complex friendship with Naaden, and the demon lord Mao (Near), who seeks an item stolen by Naaden.

Kautsu features across the initial television series, the three-episode ONA "Flips the Script," and a second season. Throughout these appearances, he remains central to the shop's daily activities and ongoing struggle against financial collapse, consistently engaging with coworkers and customers within its unconventional setting.