Background
Yennefer of Vengerberg (born Janka on Belleteyn in 1173) is one of the most powerful sorceresses on the Continent. She hails from Vengerberg, the capital of Aedirn. Born with a spinal deformity (she was a hunchback), she was mistreated in her youth before being recruited to Aretuza, the academy for sorceresses. There, she underwent magical transformation to correct her physical condition, a common practice among sorceresses. The transformation rendered her infertile, a source of lasting grief.
Relationship with Geralt
Yennefer and Geralt first met during the events of the short story "The Last Wish." To save Yennefer's life from a djinn, Geralt used his final wish to bind his fate to hers. This created an unbreakable connection between them, though their relationship has always been turbulent, marked by separations, arguments, and genuine love. In one of The Witcher 3's endings, Geralt and Yennefer retire together to a quiet life.

Training Ciri
Yennefer became Ciri's magical instructor in 1266, as described in the novel Blood of Elves. After receiving a letter from Geralt, she traveled to the Temple of Melitele in Ellander to teach Ciri how to control her chaotic magical outbursts. Yennefer became a mother figure to Ciri, and the two developed a deep bond.
Yennefer taught Ciri to harness chaos (the source of magical power in the Witcher world) and helped her begin to understand her Elder Blood abilities. This training is directly relevant to The Witcher IV, where Ciri demonstrates elemental magic that goes well beyond standard witcher signs. Her ability to channel water into electrical blasts reflects Yennefer's instruction.
Status in The Witcher IV
Yennefer has not been officially confirmed for The Witcher IV. Voice actress Denise Gough, who played Yennefer in The Witcher 3, has stated she has not been approached for the sequel as of early 2025. However, voice recording typically happens late in development, and the game is not expected until 2027 at the earliest.
Given that Yennefer and Geralt are Ciri's adoptive parents, and Geralt is confirmed to appear, many expect Yennefer to also be in the game. But CDPR has made no announcement either way.