Petra Ral was an Eldian who served as a hand-picked soldier of the Survey Corps by Levi Ackerman placed in the Special Operations Squad.
Petra was a relatively short woman with blonde hair and brown eyes. She wore the typical uniform of a member of the Survey Corps, with a white button-up shirt underneath.
Petra looked up to Levi Ackerman as a captain and cared deeply for her team, but was notably at odds with Oluo, due to his tendency to imitate Levi.
Appearance: Petra was a relatively short woman with blonde hair and brown eyes. She wore the typical uniform of a member of the Survey Corps, with a white button-up shirt underneath.
Personality: Petra looked up to Levi Ackerman as a captain and cared deeply for her team, but was notably at odds with Oluo, due to his tendency to imitate Levi. Petra was kind and caring, as shown when she looked after and guided Eren when he was first admitted to the squad.
Petra Ral in the story: During an expedition outside of Wall Rose, Petra is left to tend to injured soldiers while Levi kills nearby Titans. of the soldiers, despite Petra's efforts, bleeds out from his injuries. After the post-Trost District battle trial to decide Eren's fate concludes with Eren joining the Survey Corps, the Special Operations Squad is assigned to look after him.
How Petra Ral echoes later: When the newly established Special Operations Squad goes into hiding for Eren's and Historia's safety, Eren remembers cleaning together with Petra, and the rest of the former Special Operations Squad. Later on, while speaking to Historia under the Reiss Chapel, Eren mentions Petra as being among the victims he and Grisha Yeager are responsible for killing by stealing the Founding Titan. Later in the Battle of Shiganshina, as Erwin Smith begins to lament the dwindling hopes of his dream, Petra stands among the many fallen Survey Corps comrades in Erwin's mind, wanting to know if their deaths had meaning.
Source: Attack on Titan Wiki, available under CC BY-SA 3.0.