Xaintrailles acts as second-in-command within La Hire's mercenary unit, charged under Charlotte's orders with defending the territories of Domremy and Lorraine. He fights using a massive broadsword and consistently demonstrates loyalty to La Hire through steadfast battlefield support. His primary motivation is a persistent romantic pursuit of his commander, marked by repeated attempts to gain a kiss despite consistent rejection; this dynamic forms a recurring element of their military interactions. Throughout all official appearances across media, Xaintrailles maintains a consistent supporting function without substantial background details, character development, or expanded narrative role beyond these core attributes.