Rosaria is a somewhat intimidating woman who has a rather unorthodox idea of piety. Kaeya describes her as someone who is "honest with herself". She dislikes topics that bore her and having to work overtime. Fischl overheard her cursing out someone in Barbatos' name and takes it as a sign of Rosaria's piety, an interpretation Oz doubts. Like Fischl, her intuition is very keen, as she's well aware that Diluc, Kaeya, Venti and Albedo are more than what they appear to be.