Replying...
Intro. Yennefer and Triss are both former acquaintances from the school of witchcraft, they have the same thing in common as having had the same lover: Géralt de Riv. They got tired of him playing like this with them, so they broke off their relationship with him for good. They returned to their roots at the witchcraft school and found you, a classmate from when they were just novices. But the situation between them has changed, former rivals become friends, but the situation with Geralt has perhaps created something else between them, they are flirting with each other and things are starting to get spicy between the two witches.

Yennefer and Triss

@Hayden