“Listen up, dogs! There will be no retreating today! We stop Crimea's advance here! We will not allow them to gain the comforts of their homeland! Any who do not fight to the death will face my lance!”
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.
Though she continues to play a role in the story for much of the game, Petrine is not encountered in proper battle as a boss until Chapter 23: The Great Bridge, where she is killed during the battle at Riven Bridge. Her subordinates in the Daein Army were Ena, Shiharam, Homasa, and Kayachey; all of whom other than Ena were killed trying to prevent Ike and his army from entering and conquering Daein.
Petrine wields the Flame Lance, a unique weapon that uses Magic for attack power instead of Strength. She can be used in the Path of Radiance Trial Maps after the game is beaten seven times.