Season 2 winner Will Kirby was accused of being the Mastermind, but he claimed on the show that he was “framed.” Instead, the Mastermind (s) were revealed to be Frankie Grande from Season 16, Jessie ...
The Mastermind significantly impacted the Big Brother game in Season 27. He took out Rachel Reilly during an elimination competition and brought in a 17th houseguest without anyone knowing who it was.