Ascension at Aretuza
Fringilla is one of the initiates brought into Aretuza by a sorceress named Tissaia de Vries. She is among several other girls in the greenhouse, who much like herself can tap into chaos and perform magic. Tissaia explains the dangers of magic and how each one of them showed an aptitude for controlling it. She explains that they are conduits of chaos, though magic itself is the control of chaos. She has gathered them for a trial. Before each of them sits a flower and a stone. They are to lift the stone without touching it. Fringilla is the first initiate to lift the stone, however, as demonstrated, magic comes at a price. Only seconds after Fringilla lifts the stone does her hand rapidly age and shrivel up. There is a give and take with magic, as Tissaia demonstrates by lifting the stone, but with the flowers in hand to represent what is taken as they grow old and die. The other initiates follow her lead, with the exception of Yennefer, who is unable to move the stone at all.
Several weeks have passed since their trial with the flowers and stone. The initiates are taken to Tor Lara to bottle lightning. It's the most potent place on the continent, off-limits to everyone except to the Brotherhood of Sorcerers. This latest trial is to test their ability to control the ultimate expression of chaos. Fringilla raises her bottle and captures the lightning.
Fringilla is one of several initiates to be officially initiated into the Brotherhood. During the ceremony, she telepathically tells Istredd that Yennefer decided not to come after being assigned Nilfgaard's monarch instead of Aedirn, where Fringilla has been assigned. Later, she accompanies King Virfuril at an Aretuzan ball, until Yennefer arrives completely transformed. King Virfuril quickly discards Fringilla in favor of Yennefer, and the two dance center floor. Fringilla is instead assigned to Nilfgaard.
Several years have passed since her ascension from Aretuza. After conquering Cintra, Fringilla searches for Queen Calanthe's body. They find her on the ground, buried under snow. One of Fringilla's comrades cuts a chunk out of Calanthe's arm and eats her flesh. Fringilla then guts him and is able to determine that Ciri is in Brokilon forest.
Fringilla confronts Mousesack. He claims to know how she was schooled and shaped, which doesn't reflect her current actions. Fringilla retorts that the White Flame made her who she is. Gave her a higher purpose. Mousesack could've had that too if only he realized that Cintra had to fall. Cahir, the Black Knight, returns with a shape-shifter known as a doppler. He takes on Mousesack's appearance before killing him.
Cahir murdered everyone inside the tavern to insure they weren't the doppler, who took his form and attacked him in an attempt to gain possession of Ciri. As Fringilla cleaned his wound, he remarked that a simple test of silver would've sufficed. Fringilla stated that they could pull more soldiers and keep searching for Ciri. Fringilla reminded Cahir that it was he who rose up against the Usurper and helped free their people from their chains. She witnessed the White Flame crawl on him and anoint him. Ciri may be the key, but Cahir was the commissioner. They will find Ciri and spread the White Flame's supremacy throughout all kingdoms.
Conclave of Northern Mages
Fringilla arrived at the conclave of Northern mages and denounced any suspicion that Nilfgaard was planning to take over the continent. Under their new leader, Emperor Emhyr, Nilfgaard had strengthened trade and funded research. They tore down walls while Queen Calanthe continued to put them up. Tissaia accused Fringilla of rejecting the order and way of life that took centuries to build. Tissaia retorted that they simply modified it. They took a new path, guided by the White Flame. When Triss claimed that Nilfgaard also forced mages into servitude and practice black magic, Fringilla responded that they believed in shared sacrifice and that there was no such thing as dark or light magic. Fringilla believed that in taking Cintra, they had a chance of saving the continent. If the Northern mages won't take sides, Fringilla asked that they at least stay out her way. Stregobor and Artorius were in favor of letting Cintra fend for themselves.
Fringilla pointed out that if not for Yennefer, she never would've been assigned to Nilfgaard, and it wouldn't be the empire it is today. Artorius joked that had they sent Yennefer to Nilfgaard as planned, It would still be a "shitty backwater." Yennefer admitted this was true. Instead of Nilfgaard, she went to a prized kingdom and did "fuck all for decades." She helped murderers and rapists keep their crown. If given an option, she'd vote to burn it all down. Tissaia wagered that Cintra was scared and suggested that they lend a hand. The mages put it to a vote. Unfortunately, most side with Stregobor and Artorius to allow Cintra to fend for themselves.
Battle of Sodden Hill
After discovering that the Brotherhood was fortifying the keep, Fringilla reported back to Cahir to alert him of their arrival. The field Marshall recommended that they fall back, but Fringilla desired to move forward with the plan. This was their chance to honor the White Flame. Cahir refused to lose Princess Cirilla and ordered Fringilla to tests the Brotherhood's defenses.
Just up the mountain, Fringilla led the assault on Sodden Hill. She ordered her mages to keep attacking, but with each attack, the Brotherhood deflected. Fringilla then conjured up a small box to hand to a mage, who she ordered to draw the mages out.
Fringilla and Cahir watched from the top of the hill as their men were taken out by the brotherhood. They were forced to move to the other front. Fringilla guided eight of her own archers into a clearing in the woods, where she opened a portal that they fired arrows through, killing Vanielle and several others.
Tissaia confronted Fringilla in the woods. She offered her a way out if she would willingly returned to Aretuza. Fringilla laughed. She then explained that Nilfgaard was able to take Cintra after a horrible storm, where fifty Skelligen ships sunk to the bottom of the sea. Wrecked in a horrible fog caused by her. She then incapacitated Tissaia by throwing dimeritium in her face.
After breaking down the front line and taking out almost all of the Northern mages, Fringilla intercepted Yennefer's telepathic message. She told Yennefer to stop fighting and join Nilfgaard. However, Yennefer stayed true to her belief.