Qyburn

Qyburn was a former Maester who served as both Hand of the Queen and Master of Whisperers to Queen Cersei I Lannister. As a former Maester of the Citadel, he was stripped of his chain and expelled from the order following the discovery of his horrifically unethical experiments. By the time of the War of the Five Kings, he was residing in Harrenhal, where he survived Ser Gregor Clegane's massacre of the castle. He briefly served House Bolton before accompanying Jaime Lannister to King's Landing, where his knowledge, cunning and talents in healing quickly earned the respect of Cersei Lannister. Following Varys' disappearance, he was named Master of Whisperers, and following Cersei's ascent to the Iron Throne after the Destruction of the Great Sept of Baelor (which he helped orchestrate), he was named Hand of the Queen. Qyburn later aided Cersei in her plot to destroy King's Landing in it's entirety, but was killed by Jaime Lannister during the Siege of King's Landing upon his discovery of the scheme.