Guiche de Gramont, nicknamed Guiche the Brass, navigates Tristain Academy of Magic with suave charm and a reputation as a serial flirt, juggling romantic overtures to multiple women while harboring sincere affection for Montmorency. His public infidelity sparks scandal, forcing him to confront the fallout and his own shortcomings, yet his resolve to shield Montmorency never wavers. A master of earth magic, he channels his abilities through a wand hidden in an artificial rose, summoning bronze Valkyries in battle alongside his mole familiar, Verdandi—a testament to his elemental affinity.

Initially defined by vanity and petty mischief, like exploiting Verdandi to dig peepholes, Guiche gradually sheds his shallow noble persona. He emerges as a strategic leader, commanding the student Undine Knights as captain with Saito as his lieutenant. His lineage echoes a 17th-century French namesake famed for libertine exploits, and his surname honors a southwestern French region. Personal quirks, such as his weakness for soufflé, add levity to his arc.

Though consequences of his actions reshape his relationships, Guiche retains a flair for theatrical nonchalance, especially around noblewomen. This duality cements him as both a source of humor and a figure of unexpected depth, balancing roguish antics with loyalty and incremental growth.