William Rhett is a colonel in Charles Town.
During the events of Black Sails: Season 2 Episode 8 XVI. played by Lars Arentz-Hansen
Captain Flint, Miranda Barlow and Abigail Ashe get into the Boat Captain's boat and are taken to the Charles Town dock. William confirms who Flint is and as he is taking Flint, Miranda and Abigail through the town, Rhett tells them how Peter Ashe changed things when he committed to fighting the pirates. Rhett has his men beat Flint until Abigail orders them to stop. Rhett then takes Flint, Miranda and Abigail to Peter.
During the events of Black Sails: Season 2 Episode 9 XVII. played by Lars Arentz-Hansen
Flint starts to give his proposal to Peter, but is cut off by Peter who tells Flint and Miranda that he doesn't understand how they could be the same people he once knew. Peter asks Flint how he became a pirate captain and when he decided to murder Alfred Hamilton. Miranda tells Peter that it was her that encouraged Flint to kill Alfred. Miranda stands up and Rhett pulls out his pistol and points it at her and warns her and Flint that he will shoot them if they get any closer to Peter. Abigail knocks on the door and tells Peter that Mrs. Tyler says it is time for dinner. During dinner, Peter has Rhett and Abigail wait in the hall. Later, Miranda tells Peter that she wants to see him hang. Rhett shoots Miranda in the head and Flint charges at him and starts to strangle Rhett, but is beaten to the ground.
During the events of Black Sails: Season 2 Episode 10 XVIII. played by Lars Arentz-Hansen
Kensington shows the crowd the evidence against Flint and asks Flint if he has anything to say in his defense. Flint says that the only thing he regrets is believing that he and Peter could come to reason. A Militia Guard walks up to Peter with a handcuffed Captain Charles Vane. Vane tells him that he has testimony in support of Flint and it is from Abigail's journal, which is handed to Peter. A Clerk reads aloud from Abigail's journal.
Vane makes a speech and raises his hands to the air. Vane's men then start firing upon the town square with the town's own cannons. Vane and Flint attack their guards and Flint and Vane get into a boat and start to row towards the Man-o'War and are fired upon by Rhett and some militia men. The Man-o'-War opens fire on Rhett and kills him.