Yennefer was born in Vengerberg and was the youngest wizard to be admitted to the Council of Sorcerers, underlining her vast magical abilities.
Yennefer and Geralt met when he was looking for someone to cure Dandelion, who got severely hurt by a crazed Djinn, to which she agrees.
Geralt's immediately fascinated with her and when Yennefer makes a futile attempt to overpower and capture the Djinn, he utters a wish so their fates will be bound to each other forever, preventing the Djinn from killing her.
Yennefer serves as a mother figure and mentor to Ciri.
Yenenefer was mentioned in the first two games, but makes here real debut in The Witcher 3.