Be forewarned that a sorceress has arrived on Ard Skellig. Her name is Yennefer and she hails from Vengerberg. I know you are immune to feminine wiles and will not let a well-draped skirt muddle your reasoning. Nevertheless, I warn you not to be taken in by her intelligence and refinement. I know who Yennefer is — I do not, however, know the true goal of her stay in Skellige. I see no point in asking her this question directly, for Yennefer is known for her cunning and eloquence. She says not what she thinks, but what she wishes you to hear. You must remember this is no second-rate sorceress. This is a person who breaks bread with the rulers of the North and who most recently has been working with the Nilfgaardian emperor himself. Familiar with courts the world over, she possesses an ability to manipulate that even the wiliest diplomat would envy.
Yennefer has displayed an unhealthy interest in the site of the cataclysm we are striving to study. I have not given her permission to go near it, but I caution you to keep your eyes and ears open all the same. The sorceress from Vengerberg is a stubborn and effective manipulator. I know that in the past her and Crach's paths crossed. I suspect that she will wish to use this old friendship for some ulterior purpose. What that is, exactly... I will try to determine. Once I do, I will inform you in a separate letter.
May the Power be with you, Brothers