Charles du l'Etoile, once commander of the Alpha Tactics Armored Corps’ 15th Squad, enters the series stripped of rank following a romantic scandal that cements his womanizing reputation. Despite his demotion to private, his technical combat expertise remains sharp, even as his disregard for protocol strains military decorum.

Initially defined by playful flirtations, his trajectory shifts upon encountering Marie Angel—a formidable comrade dubbed the "Cosmo Amazon." Their relationship, born from friction, deepens into a nuanced bond marked by Marie’s guarded resistance and eventual emotional reciprocity. This evolution reveals vulnerability beneath his cavalier exterior, contrasting his earlier superficial liaisons.

Within the 15th Squad, his seasoned instincts clash with Jeanne Francaix’s brash leadership, embodying tensions between discipline and individualism during missions against the Zor. Though his tactical acumen occasionally resurfaces from his command experience, his reduced rank curtails formal influence.

Central to his arc is the evolving connection with Marie, which anchors his emotional growth. Despite his roguish persona, unwavering loyalty to the squad and deepening investment in Marie hint at complexities beyond his initial portrayal.