Mr Brock ran the New York branch of the company Harmony Shoal. At some point he confronted Dr. Sim about the true intentions of Harmony Shoal, and he learned that Sim's body had been taken over by an alien. Brock was soon subject to the same fate and had his brain removed to make way for one of the Shoal. (TV: The Return of Doctor Mysterio)
Behind the scenes
Brock is one of Shoal of the Winter Harmony enemies in Doctor Who Legacy mobile game.