Marcus is a doctor in the British Army.
During the events of Black Sails: Season 3 Episode 8 XXVI. played by Wayne Harrison
During the events of Black Sails: Season 3 Episode 9 XXVII. played by Wayne Harrison
Rogers has a meeting with his senior counselors and Dr. Marcus tells Eleanor that he has confined Rogers to bed after Rogers collapsed. Mr. Soames asks Rogers how long they should wait for Captain Benjamin Hornigold to return with word that he has regained the cache. Rogers tells his counsel that if Hornigold fails to recover the cache they will try again and that until he is well, Eleanor is to be given what messages they want to pass to him.
During the events of Black Sails: Season 3 Episode 10 XXVIII. played by Wayne Harrison
Dr. Marcus calls for Eleanor and she goes to see Rogers.