Petra is an Oseram inventor from the settlement of Free Heap. When she and her people came across some valuable machine parts, a clan of bandits and some Scrappers stole much of their goods and tried to take their claim. Petra hires Aloy to take back the goods, which provokes the bandits to commit a full-scale assault on Free Heap. Fortunately, Petra uses the recovered parts to complete her prototype Oseram Cannon, which Aloy uses to lay waste to the bandits, saving the claim and gaining Petra's gratitude. Later, Aloy and Petra meet again after Aloy obtains some Behemoth cables for her.