Caroline

From Witcher Wiki

Caroline was Alvin's foster mother. She died in the fangs of barghests one night on her way to the Inn with the boy in the opening sequence of Act I. We know she wasn't his biological mother because of a conversation Alvin has with Geralt at the Inn the following day. During that conversation, Alvin mentions that his parents were already dead and that he has not other kin whatsoever.