Corinne Tilly is an oneiromancer, a mage who specializes in reading and interpreting dreams. Like most mages in Novigrad, she lives in hiding from the witch hunters, taking the odd job when she needs money.

In The Witcher 3

One of those jobs goes badly. A banker, Rudolf de Jonkheer, hires her to dream up the history of a haunted house he has just bought. The haunting is really the work of Sarah, a godling living in the house, who traps Corinne in endless nightmares. Geralt breaks the spell in Haunted House while looking for someone who can help him find Ciri.

Grateful, Corinne meets him at the Golden Sturgeon in Novigrad Dreaming and places him in a dream in which he glimpses Ciri seeking out Dandelion. That points him to the Rosemary and Thyme. Later, in Through Time and Space, Geralt turns to her again when he needs to show the elf Ge’els the truth about Eredin’s murder of King Auberon. Without quite realizing it, she helps weaken the Wild Hunt’s leader. If Geralt let Sarah stay, the godling and the sorceress end up sharing the house happily.