<Tr> <Th> Title </Th> <Td> M.D. </Td> </Tr> <Tr> <Th> Significant other (s) </Th> <Td> Megan Hunt Meredith Grey </Td> </Tr> <P> Nathan Riggs M.D., is a fictional character from the television medical drama Grey's Anatomy which airs on the American Broadcasting Company (ABC) in the United States . The character was created by series producer Shonda Rhimes and is portrayed by actor Martin Henderson . He was introduced in the episode "The Me Nobody Knows". He is a cardiothoracic surgeon who works with April Kepner during her time in Jordan . After bringing a patient to Grey Sloan Memorial Hospital, he is employed there . At the hospital, he forms a romantic attraction to Meredith Grey, now a widow after the death of Derek Shepherd . </P> <P> Nathan Riggs is introduced in the sixth episode of the show's twelfth season as a new cardio attending at Grey - Sloan Memorial Hospital . It is quickly learned that he and Owen Hunt had been friends, but their friendship ended acrimoniously . It is later revealed that Riggs and Owen Hunt were best friends, and Nathan was engaged to Hunt's sister Megan Hunt at one point . Owen blames Riggs for the disappearance of his sister, as the reason she got in a helicopter with a patient in the first place was because she had discovered that Nathan had been cheating on her and wanted to get away from him; she left and the helicopter went missing while in flight and never made it to its destination and Megan, and the rest of the helicopter's passengers, is presumed dead . </P>

Who is nathan riggs in grey's anatomy