Petrine is one of Daein's Four Riders during The Mad King's War. She first appears as part of the Daein force that pursues the Greil Mercenaries during their flight to Gallia with Princess Elincia. Her forces briefly catch up with the mercenaries in Chapter 7: Shades of Evil, and she manages to confront Greil directly, but the encounter is cut short when laguz led by Ranulf arrive, spooking her soldiers. Petrine refuses to retreat, suggesting she would be punished by Ashnard for doing so. However, the Black Knight, another of Daein's Four Riders, appears and orders Petrine to retreat, at which point she takes her leave.