Tissaia de Vries/Netflix series

Tissaia de Vries is a sorceress and a member of the Chapter of the Gift and the Art. She's also the rectoress of Aretuza. She recruits young woman who have conduit moments.

Recruiting Yennefer
Tissaia de Vries recruits Yennefer from her home town of Vengerberg after Yennefer unintentionally portals to Aretuza briefly. Tissaia finds Yennefer and purchases her for four marks from her father, less than half the price of a pig. Her mother objects, though it goes without answer, as does Yennefer’s cry for help. Yennefer is forcefully taken from her home in Vengerberg and locked in a room in Aretuza. Yennefer shatters the mirror in her room and grabs a shard of glass as she contemplates taking her own life.

Tiassai heals Yennefer after she slit her wrists. Yennefer, however, wishes she had died, claiming that at least she would’ve had control over that. Tiassai retorts that Yennefer wasn’t taking control, she was losing it.

Later, the greenhouse is occupied by several young ladies, who much like Yennefer, can tap into magic. Tiassai explains the dangers of magic to them and how each one of them showed an aptitude for controlling it. They are conduits of chaos, although 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 Tiassai demonstrates by lifting the stone, but with the flowers in hand to represent what is taken as the flowers grow old and die. The remaining initiates follow her lead, with the exception of Yennefer, who is completely unable to move the stone in any manner. Discouraged by her failed attempt, Yennefer flees the greenhouse.

Several weeks have passed since Yennefer’s arrival in Aretuza, and the initiates now sit across from each other during an exercise to determine their partner’s greatest fear. Telepathy should be taking place, however, after hours of analyzing her partner, Yennefer fails to determine her fear and lies to cover up her inadequacies. Tiassai immediately identifies it, calling Yennefer out and berating her in front of the class.

Tissaia later takes the initiates 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. After watching two initiates fail before her, Yennefer’s up. She raises her bottle and fails; the lightning striking her and sending her across the room. Enraged by her own failures, Yennefer shoots the lightning at Tissaia, and she redirects it back into the sky. Tissaia relates to Yennefer. There are two types of mages. Those who can control their emotions and those who let their emotions control them, Yennefer and Tissaia being the latter. It’s their job to control chaos, not become it.

Yennefer takes the flower she got from Istredd to Tissaia. This was a test orchestrated by Tissaia to see if Yennefer could control her emotions long enough to get it from him. She did so successfully, and Tissaia dismisses her, referring to Yennefer by her actual name rather than "Piglet." Yennefer asks if this means she’s ready to "ascend." Tissaia tells Yennefer to listen for the knock.

Yennefer listens for the knock as instructed. However, it’s not her door that Tissaia knocks on. Nevertheless, she takes the opportunity to spy on Tissaia as she turns three of the initiates into eels. Tissaia instructs her to push them into the water. Tissaia took away their control, but they still have power. They’re conduits for Aretuza. So when Yennefer takes a broom and pushes them into the water, all of Aretuza lights up with magic.

Sending Yennefer to Nilfgaard
Tissaia finds Yennefer with the enchanter in preparation for initiation. Tissaia tells Yennefer that they remake themselves on their own terms. Yennefer has the power to free the "victim in the mirror" forever. Tissaia instructs Yennefer to close her eyes and imagine the most powerful woman in the world. Yennefer opens her eyes and sees just that looking back at her in the mirror, if only for a brief moment, drawn from Yennefer’s mind onto the mirror by Tissaia’s magic.

The Chapter gathers to discuss their concern with Cintra refusing to use their mages. King Dagorad has banned mages from Cintra entirely, and although Stregobor has heard rumblings that the king is ill, assuming Princess Calanthe will be more inclined to accept their mages if he dies, but Tissaia is doubtful. Artorius asks what of Nilfgaard, and Stregobor criticizes King Fergus for squandering the kingdom’s money on women while his people starve to death. Fringilla, Artotius’ niece, will be in Nilfgaard by week’s end, and Tissaia assures everyone that she will bring sanity and bread to the kingdom. However, Stregobor has little faith in her. Artorius suggests sending someone with a bit more "spine" to Nilfgaard, and Stregobor recommends Yennefer, since they’d be spitting in Dagorad’s face to send her to Aedirn, Cintra’s biggest trading partner. The only thing Cintra hates more than mages is elves, and Yennefer is a quarter-elf. Tissaia is very much against sending Yennefer to Nilfgaard, even accusing Artorius of nepotism for sparing his niece of her duties. The chapter puts it to a vote, and Tissaia is overruled; Yennefer is reassigned to Nilfgaard.

Tissaia is confronted by Yennefer, who demands an audience with the Chapter after discovering that she is being sent to Nilfgaard rather than Aedirn as promised. Tissaia reveals that it was her blood that finalized the Chapter’s decision. Sending a quarter-elf to Aedrin would only further ostracize Cintra given their hatred for elves. It was Stregobor who told the Chapter about Yennefer’s true father.

Tissaia, Artorius, Stregobor, and the rest of the Chapter gather to initiate the new recruits into the Brotherhood, which Yennefer does not attend following her reassignment. However, she does attend the Aretuzan ball completely transformed. King Virfuril discards Fringilla in favor of Yennefer, and the two dance center floor with Tissaia, Artorius, and Stregobor watching angrily.

A Shot at Redemption
It's been over 30 years since they last spoke, but with Yennefer drawing unwanted attention, Tissaia decides to pay her a visit. Tissaia informs Yennefer that King Virfuril is dead. King Demavend rules now. Yennefer remained hidden for a while, but now she’s making noise in search of a solution to her problem; she wishes to bare children. Tissaia has come to warn her, saying that the mages that Yennefer is enlisting won’t help her because Yennefer is "pure chaos" at the moment. She wants a cure, and it’s making her sloppy. The Brotherhood left her to her own devices after she abandoned Aedirn, but her recent behavior will make her a target. Tissaia invites Yennefer to return to Aretuza, but she turns Tissaia down. Yennefer suspects that Tissaia only wants to see her thrive so long as she has a hand in it. Tissaia swears this is not true. She questions what more Yennefer could want, to which she replies "everything."