Frigga

"Everyone fails at who they're supposed to be, Thor. The measure of a person, of a hero... is how well they succeed at being who they are."

- Frigga to Thor

Frigga was the Queen of Asgard and wife of Odin, mother of Hela, Thor, Aurora and adoptive mother of Loki. In A Royal Object, she is mentioned multiple times, the first being in the second chapter. She never truly appears in the fanfic, shockingly.