Mother Isolde

Mother Isolde is a character appearing in Fallout 4.

Background
During the The Glowing Sea quest the Sole Survivor is guided to the Glowing Sea and questions Mother Isolde as to the whereabouts of Virgil (who is in hiding in a cave southwest of the Crater of Atom). She knows of his location because of a note from Brother Hoberman and will provide the information. She will also note that they are concerned about his presence which is seen as an affront to Atom by some of the followers.

Other interactions
There are further dialogue options to learn more about why she and the other followers are in the Glowing Sea, how they survive in the radiation and generally about the Church of the Children of Atom.

Appearances
Mother Isolde appears only in Fallout 4.

Behind the scenes
Her name is possibly a reference to ISOLDE (an acronym for Isotope Separator On Line DEvice) which is an experimental infrastructure within the CERN complex of nuclear and particle physics experiments.