Petra initially acts contemptuous and hostile towards students from the other houses. Along with the other Jeturk students, she enables the bullying behavior of classmates like Guel and is confrontational with students she views as lesser. She also indulges in following school gossip. Her loyalty to her Jeturk friends causes her to overlook or excuse some of their own negative traits.

Despite her caustic behavior to others, Petra cares for her friends and fellow house students and is dedicated to assisting them. She is very supportive of Lauda, as she takes on secretary duties for him in addition to her normal school work. She can act compassionate to people outside of her social circle, and she gradually tries to make amends with people she had previously bullied. In serious situations, she is even willing to risk her life to save and rescue others despite her personal grudges.

While initially hostile to Suletta Mercury, Petra slowly warms up to her after she fought to save the students on campus, and she even begins helping her upon noticing her depressive state from recent events.