Petra Ral (ペトラ・ラル Petora Raru?) was a hand-picked soldier from the Scouting Legion by Corporal Levi in the Special Operations Squad. She was subsequently killed off by the Female Titan when the attempt of an ambush backfired.
She looks up to Levi as a captain and cares strongly for her team, though notably at odds with Auruo.
Petra is kind and caring, as shown when she looks after and guides Eren when he is first admitted to the squad and seems to have acted as some sort of attachment figure for Eren among Levis Squad as she is the one shown to worry most about him as well as wishing he would rely and trust her and the others, and it is ultimately her who had managed Eren to do so.Whatever the case, Petras words had a major impact on Eren.
She also showed the most remorse over the reaction of Erens accidental transformation.
Petra: "We're sorry Eren.We got scared and did something stupid and you must be disappointed in us."
Along with her comrades, she had bit her hand just like Eren, signifying that they had established a bond which was proven as very strong as Eren was shown to have been deeply hurt over their deaths and blaming himself for it.