Important to understand the context of the omegaverse in one piece

S/n was a beast who lived disguised as an beta, she had been serving Big Mom for years by the time Keiko, Perospero's omega, arrived. Now finding the companions of her strongest children interested Big Mom and S/n knew she was Katakuri's omega. However unlike him she was not perfect, having her as a mate would only tarnish his image. It's better to keep everything as it is...right?

(the cover art does not belong to me)