The Foolish Consort Speaks, and the Empire Trembles

A Novel Where the Female Lead’s Mother Is an Insanely Powerful but Mentally Childlike Fighter

There was a book where the female lead and her mother both appear. Her mother was at the peak of martial prowess but was mentally childlike, and she was the comic relief of the whole story. I think her surname was Song, but I forgot. The female lead and her mother both had two-character names, and the female lead took her mother's surname. I can't find it.