Pia is a young thief in the second RuneScape novel Return to Canifis. She originally hails from Ardougne, but left with her younger brother Jack after they become wanted criminals. She was part of a gang of thieves, which also included 2 thieves called Thorn and Ginny. Her motto is "Never a rope."
During Return to Canifis, Pia pretends to be the legendary heroine Kara-Meir as part of a plot with the Phoenix gang to con the civilians of Varrock into giving their money to her, claiming it will be redistributed among the less fortunate. She and Jack attempt to flee the next morning, but get she captured and handed over to a band of outlaws led by Sulla.
Pia, whilst Sulla's prisoner, finds some wolfbane daggers, and uses one of them to wound Jerrod during her initial escape attempt, which fails. After Jerod and Sulla leave, Pia attempts another escape attempt, but is again quickly overcome. During this attempt, the real Kara-Meir rescues her and kills all but one of her remaining captors. She is reunited with Jack and they travel with Kara, Gar'rth and Arisha to Varrock, where Pia and Jack become Kara's servants in exchange for Kara gaining them pardons for their theft. They steal a horse and flee after being accused of murder by a Kandarin ambassador, and make their way east towards Morytania. Shortly after crossing the River Salve into Morytania, they are attacked by a ravenous vampire, but somehow manage to escape. They are captured by werewolves outside the town of Canifis, along with Vanstrom Klaus. Despite pleas by members of the embassy from Misthalin, she and Jack are not released or exchanged.
After the town is attacked by members of the Myreque resistance group, she, along with Jack and Vanstrom, manage to escape to one of the group's hideouts, where they plan an escape to Misthalin. During this time Pia is implied to develop feelings for Vanstrom, to the point where she kills another member of the Myreque. She joins the rest of the Myreque on the balloon which gets taken down by vyrewatch under the employment of Vanescula Drakan, and manages to survive the subsequent attack by werewolves.
After managing to swim back across the Salve, Pia and Jack join the rest of the Myreque in trekking to Varrock, but are attacked by Zamorakians trying to steal the body of Albertus Black. She and Jack hide in the woods and are tracked by a mage and ranger, who are taken out by Kara-Meir. She and Jack enter domestic servitude at Varrock Palace afterwards, under the watchful eye of Lucretia.
When the Misthalian army moves to Paterdomus, Pia becomes a messenger for the guard located in King Botolph's Tower, where Felicity, the last surviving child wanted by Tenebra, is guarded. A disembodied voice taunts her while she is doing this. During the Battle of King Botolph's Tower, she breaks into the nobles' wing of the palace on the order of Lady Anne to release Lord William, by this point a wanted fugitive.