Kikyou Saionji

Usagi's step mother and the current matriarch of the Sainoji Household. Due to Usagi's position as a illegitimate daughter from a mistress, Kikyou resented Usagi as she deemed as an outsider to the family and actively avoided being referred to as her mother. This relationship is further strained when Usagi is blamed for the death of proper heirs to the family. On Usagi's end, she unconditionally respected Kikyou but through the events of the story, mostly moved away from her family name.

(Source: Taimadou Gakuen 35 Wiki)