Kettricken is eighteen years old when she is betrothed to Verity Farseer. Despite her youth, she is serious about her duties as Queen-in-Waiting and as Sacrifice for the people of Buck. As a result of finding herself sometimes overwhelmed by the traditions of the Six Duchies, she attempts to recreate the aesthetics of the Mountain Kingdom in her personal quarters and the Queen's Garden.
Kettricken is mildly Witted, although she does not recognize it as such. She reports feeling "connected" to the world when she meditates. She also becomes close to Nighteyes, and at times seems able to understand him.
Kettricken is warned by Regal that the Buck contingent arriving in Jhaampe to perform her marriage to Verity will contain an assassin targeting Rurisk. When she meets FitzChivalry Farseer, she acts enthusiastic about his interest in herbs and insists on bringing him to her gardens. She makes him sample several herbs, disguising the fact that one of them is a poison by discussing each leaf's taste and culinary uses.
Fitz begins to talk positively of Verity, which surprises Kettricken. She informs Fitz that Regal had described Verity as being very old and feeble. This makes Kettricken question her convictions, but Fitz has already begun to feel the effects of the poison, and he departs rapidly. Kettricken agonizes over her actions most of the night before finally confessing to Rurisk.
Kettricken accompanies Rurisk to Fitz's chambers, where they discover he is still alive. Rurisk scolds Kettricken for her hastiness. Kettricken is skeptical of her brother's safety after Fitz admits that he was sent with the assignment of poisoning Rurisk. However, Rurisk reassures her by pointing out that Fitz can no longer assassinate him in any way without Kettricken or their aunt Jonqui accusing Fitz of the deed. Kettricken reaffirms her commitment to marrying Verity despite this treachery, impressing Fitz.
The next night, Fitz arrives at Kettricken's door and informs her that he is on his way to poison Rurisk, having been ordered to do so by Regal. Disturbed, Kettricken follows him, where she discovers Fitz and Rurisk drinking a bottle of apple wine from the wedding gifts. Kettricken warns her brother of Fitz's betrayal, but Rurisk explains that Fitz put poison in the glass now set aside. He then upsets her by pretending to feel the effects of the poison. The three discuss Regal's obvious intention to rid himself of Fitz by publicly accusing him of Rurisk's murder; they are interrupted by Cob, who is meant to witness the act. However, Rurisk then begins suffering the real effects of the poison that had earlier been placed in the bottle of wine. Kettricken, believing Fitz responsible, prevents him from escaping by knocking him out.
After Rurisk's death, Kettricken comes to the conclusion that Fitz is not the responsible party, and takes advantage of her right as kin to forgive her brother's accused murderer. Kettricken orders Fitz to return to the palace and proceeds with her wedding. In Buckkeep, Verity is warned of Galen's treachery by Fitz; he uses Fitz's lent strength to kill Galen and to appear in Kettricken's mind through August. Kettricken is awed by Verity's display of strength and vulnerability. She moves to Buckkeep with much optimism about her marriage.
When she arrives in Buckkeep, Kettricken struggles to adjust to her changed lifestyle. She is surprised by court customs and restricted from her usual activities. She is also very lonely, as Verity has little time for her. Fitz gently points out that her dissatisfaction is negatively affecting her reputation and influence among the other nobles, and suggests some actions that may increase their appreciation of her. Kettricken is grateful for this, and eventually Fitz becomes a more constant advisor to her.
Kettricken is charmed by Regal, despite her knowledge of his involvement in her brother's murder. Riding horses with Regal gives Kettricken some respite from loneliness and boredom. One evening, however, Regal abandons Kettricken in the woods outside of Buckkeep, claiming to spy a fox and riding off with great haste. Kettricken is set upon by three Forged Ones. She defends herself, and manages to kill them with the assistance of Fitz, who had come upon her struggle by chance. Kettricken returns to Buckkeep safely, but is embarrassed by Verity, who scolds her for putting herself in danger instead of commending her for defending herself.
The next day, Kettricken herself leads the hunting party assembled to eradicate the large numbers of Forged Ones near Buckkeep. Kettricken brings a gravitas to the endeavor by reminding the hunters that they are killing their own people. She participates in the hunt as well, and insists that the bodies of the Forged Ones are brought into the castle. She then assists in washing the bodies and preparing them for cremation. Kettricken's actions earn her much respect from her subjects. Chade rejoices over her graceful and capable shouldering of the mantle of queenhood.
After the end of the Red Ship War, she brings Chade Fallstar out from the shadows and appoints him as her adviser and councillor. She instills in her son Dutiful the Mountain ways and his duty as Sacrifice for his people. She is a strong and capable queen and she holds Fitz in the highest regard. She considers Fitz as Sacrifice to the Farseer reign and he is one of her closest friends.