Manissa was Mousesack's mother and a witch in the service of Fregenal. She was killed in self-defense by Korin (the future father of Geralt). Mousesack's father left Manissa when the future druid was still a small child.
In "Droga bez powrotu", ("A Road with No Return") Mousesack unwittingly teams up with his mother's killer. Not knowing that Korin had killed Manissa, the young Mousesack befriended him and the druid, Visenna, who took him to the druid circle in Mayena. She also appears in the short story "Droga, z której się nie wraca" which tells almost the same tale, but without Mousesack.