Geralt of Rivia was a legendary witcher of the School of the Wolf active throughout the 13th century. He loved the sorceress Yennefer, considered the love of his life despite their tumultuous relationship, and became Ciri's adoptive father.

During the Trial of the Grasses, Geralt exhibited unusual tolerance for the mutagens that grant witchers their abilities. Accordingly, Geralt was subjected to further experimental mutagens which rendered his hair white and may have given him greater speed, strength, and stamina than his fellow witchers.