Spiritia Rosenberg [RKS001 Eins] (スピリティア・ローゼンベルク, Supiritia Rōzenberugu), also referred to by her friends as Tia (ティア, Tia) is the first member of the RKS and the main protagonist of Rosenkreuzstilette. Spiritia has been a close friend to Freudia Neuwahl since her childhood, and also has a fairy friend by the name of Lilli.