Mrs. Froste is the mother of Sera and the wife of Mr. Froste. She, along with her husband, were not present during Sera's childhood, so Sera never knew them, although she did have Remnants about them.

In the Books

The Trap Door

When Sera warped to the Cataclysm, Sera saw her parents in her barn, dead, implying that they came back for their daughter.

Behind Enemy Lines

Tilda tells Sera that Mrs. Froste, along with her husband, were SQ. It is confirmed in Eternity.