Its cover art was in the same style as the old cover of Death Is the Only Ending for the Villainess. Unfortunately, I only read the beginning, but I remember the story involved a noblewoman with white hair who had died. This woman had a friend with black hair. I believe she had been taken into the family as a child to serve as a playmate for the white-haired woman. After the white-haired woman died, the black-haired woman wanted to leave the family. Then, four or five men, who had also been friends with the white-haired woman, tried to stop the black-haired woman from leaving (?), arguing that she had been the white-haired woman's friend.
Unfortunatly, that's the only thing I remember. Does anyone know the name?