Kathy Hilton joined “Real Housewives of Beverly Hills” in season 11.

Lisa Rinna said Hilton threatened to ruin NBC, Bravo, and the show’s cast.

Hilton promised to ruin Richards and her family.

Richards refused to follow Hilton home from the club.

Sutton Stracke said Hilton was upset because no one wanted to do the Congo line with her.

Richards said she started fighting with Hilton when they were much younger.

She said their fights became complicated once they got on television.

Fans criticized Richards for mocking Hilton during the Aspen trip.

Hilton tried to promote a tequila brand she invested in but was ignored.