Act 1

Petrice, under the name Sister Petrice, is first encountered in the quest Shepherding Wolves, in which she asks Hawke to escort a Qunari mage out of Kirkwall for her to save him from being killed by the Arishok. During the quest, it is revealed that Petrice had set Hawke up to be killed by the Qunari in a way that would generate outrage against them. She mentions that she specifically picked Hawke, as he/she had no influence in the city, therefore nobody would believe him/her if he/she were to survive. Upon completion of the quest, Hawke is given his/her reward for the deed and Petrice leaves.

Act 2

Petrice, now a Mother, is seen again in during the quest, Offered and Lost, in which she prevents Hawke from speaking with Grand Cleric Elthina regarding the Chantry's apparent involvement in kidnapping and murdering Qunari diplomats. She does give Hawke information that leads to the templars guilty of the act.

She is seen once more in the quest Following the Qun. She murders Viscount Dumar's son Saemus, who has converted to the Qun. She attempts to frame Hawke, who has had dealing with the Qunari, for the deed, but Elthina does not believe her and insists she will be arrested and see justice. At this moment, Petrice is killed by a Qunari bowman, an act of vengeance for the killing of Saemus.

If instead you chose to support Ser Varnell earlier, you will have the option to support Petrice and her zealots, in which case she will not be killed by the Qunari and the murder of Saemus will be pinned on the Qunari, but the Grand Cleric will strip Mother Petrice of her title, saying that she "failed to maintain the solemn dignity" of her position. Later, after you leave the Chantry, Petrice will tell you that if you ever need her support, she will be there to aid you.

Act 3